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OpenCloudOS-Kernel/arch/arm64/kernel/ptrace.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Based on arch/arm/kernel/ptrace.c
*
* By Ross Biro 1/23/92
* edited by Linus Torvalds
* ARM modifications Copyright (C) 2000 Russell King
* Copyright (C) 2012 ARM Ltd.
*/
#include <linux/audit.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/nospec.h>
#include <linux/smp.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/seccomp.h>
#include <linux/security.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/perf_event.h>
#include <linux/hw_breakpoint.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/elf.h>
#include <asm/compat.h>
#include <asm/cpufeature.h>
#include <asm/debug-monitors.h>
#include <asm/fpsimd.h>
#include <asm/pointer_auth.h>
#include <asm/stacktrace.h>
#include <asm/syscall.h>
#include <asm/traps.h>
#include <asm/system_misc.h>
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
struct pt_regs_offset {
const char *name;
int offset;
};
#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
#define REG_OFFSET_END {.name = NULL, .offset = 0}
#define GPR_OFFSET_NAME(r) \
{.name = "x" #r, .offset = offsetof(struct pt_regs, regs[r])}
static const struct pt_regs_offset regoffset_table[] = {
GPR_OFFSET_NAME(0),
GPR_OFFSET_NAME(1),
GPR_OFFSET_NAME(2),
GPR_OFFSET_NAME(3),
GPR_OFFSET_NAME(4),
GPR_OFFSET_NAME(5),
GPR_OFFSET_NAME(6),
GPR_OFFSET_NAME(7),
GPR_OFFSET_NAME(8),
GPR_OFFSET_NAME(9),
GPR_OFFSET_NAME(10),
GPR_OFFSET_NAME(11),
GPR_OFFSET_NAME(12),
GPR_OFFSET_NAME(13),
GPR_OFFSET_NAME(14),
GPR_OFFSET_NAME(15),
GPR_OFFSET_NAME(16),
GPR_OFFSET_NAME(17),
GPR_OFFSET_NAME(18),
GPR_OFFSET_NAME(19),
GPR_OFFSET_NAME(20),
GPR_OFFSET_NAME(21),
GPR_OFFSET_NAME(22),
GPR_OFFSET_NAME(23),
GPR_OFFSET_NAME(24),
GPR_OFFSET_NAME(25),
GPR_OFFSET_NAME(26),
GPR_OFFSET_NAME(27),
GPR_OFFSET_NAME(28),
GPR_OFFSET_NAME(29),
GPR_OFFSET_NAME(30),
{.name = "lr", .offset = offsetof(struct pt_regs, regs[30])},
REG_OFFSET_NAME(sp),
REG_OFFSET_NAME(pc),
REG_OFFSET_NAME(pstate),
REG_OFFSET_END,
};
/**
* regs_query_register_offset() - query register offset from its name
* @name: the name of a register
*
* regs_query_register_offset() returns the offset of a register in struct
* pt_regs from its name. If the name is invalid, this returns -EINVAL;
*/
int regs_query_register_offset(const char *name)
{
const struct pt_regs_offset *roff;
for (roff = regoffset_table; roff->name != NULL; roff++)
if (!strcmp(roff->name, name))
return roff->offset;
return -EINVAL;
}
/**
* regs_within_kernel_stack() - check the address in the stack
* @regs: pt_regs which contains kernel stack pointer.
* @addr: address which is checked.
*
* regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
* If @addr is within the kernel stack, it returns true. If not, returns false.
*/
static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
return ((addr & ~(THREAD_SIZE - 1)) ==
(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
on_irq_stack(addr, NULL);
}
/**
* regs_get_kernel_stack_nth() - get Nth entry of the stack
* @regs: pt_regs which contains kernel stack pointer.
* @n: stack entry number.
*
* regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
* is specified by @regs. If the @n th entry is NOT in the kernel stack,
* this returns 0.
*/
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
addr += n;
if (regs_within_kernel_stack(regs, (unsigned long)addr))
return *addr;
else
return 0;
}
/*
* TODO: does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* Called by kernel/ptrace.c when detaching..
*/
void ptrace_disable(struct task_struct *child)
{
/*
* This would be better off in core code, but PTRACE_DETACH has
* grown its fair share of arch-specific worts and changing it
* is likely to cause regressions on obscure architectures.
*/
user_disable_single_step(child);
}
#ifdef CONFIG_HAVE_HW_BREAKPOINT
/*
* Handle hitting a HW-breakpoint.
*/
static void ptrace_hbptriggered(struct perf_event *bp,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
const char *desc = "Hardware breakpoint trap (ptrace)";
#ifdef CONFIG_COMPAT
if (is_compat_task()) {
int si_errno = 0;
int i;
for (i = 0; i < ARM_MAX_BRP; ++i) {
if (current->thread.debug.hbp_break[i] == bp) {
si_errno = (i << 1) + 1;
break;
}
}
for (i = 0; i < ARM_MAX_WRP; ++i) {
if (current->thread.debug.hbp_watch[i] == bp) {
si_errno = -((i << 1) + 1);
break;
}
}
arm64_force_sig_ptrace_errno_trap(si_errno,
(void __user *)bkpt->trigger,
desc);
}
#endif
arm64_force_sig_fault(SIGTRAP, TRAP_HWBKPT,
(void __user *)(bkpt->trigger),
desc);
}
/*
* Unregister breakpoints from this task and reset the pointers in
* the thread_struct.
*/
void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
{
int i;
struct thread_struct *t = &tsk->thread;
for (i = 0; i < ARM_MAX_BRP; i++) {
if (t->debug.hbp_break[i]) {
unregister_hw_breakpoint(t->debug.hbp_break[i]);
t->debug.hbp_break[i] = NULL;
}
}
for (i = 0; i < ARM_MAX_WRP; i++) {
if (t->debug.hbp_watch[i]) {
unregister_hw_breakpoint(t->debug.hbp_watch[i]);
t->debug.hbp_watch[i] = NULL;
}
}
}
void ptrace_hw_copy_thread(struct task_struct *tsk)
{
memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
}
static struct perf_event *ptrace_hbp_get_event(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx)
{
struct perf_event *bp = ERR_PTR(-EINVAL);
switch (note_type) {
case NT_ARM_HW_BREAK:
if (idx >= ARM_MAX_BRP)
goto out;
idx = array_index_nospec(idx, ARM_MAX_BRP);
bp = tsk->thread.debug.hbp_break[idx];
break;
case NT_ARM_HW_WATCH:
if (idx >= ARM_MAX_WRP)
goto out;
idx = array_index_nospec(idx, ARM_MAX_WRP);
bp = tsk->thread.debug.hbp_watch[idx];
break;
}
out:
return bp;
}
static int ptrace_hbp_set_event(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx,
struct perf_event *bp)
{
int err = -EINVAL;
switch (note_type) {
case NT_ARM_HW_BREAK:
if (idx >= ARM_MAX_BRP)
goto out;
idx = array_index_nospec(idx, ARM_MAX_BRP);
tsk->thread.debug.hbp_break[idx] = bp;
err = 0;
break;
case NT_ARM_HW_WATCH:
if (idx >= ARM_MAX_WRP)
goto out;
idx = array_index_nospec(idx, ARM_MAX_WRP);
tsk->thread.debug.hbp_watch[idx] = bp;
err = 0;
break;
}
out:
return err;
}
static struct perf_event *ptrace_hbp_create(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx)
{
struct perf_event *bp;
struct perf_event_attr attr;
int err, type;
switch (note_type) {
case NT_ARM_HW_BREAK:
type = HW_BREAKPOINT_X;
break;
case NT_ARM_HW_WATCH:
type = HW_BREAKPOINT_RW;
break;
default:
return ERR_PTR(-EINVAL);
}
ptrace_breakpoint_init(&attr);
/*
* Initialise fields to sane defaults
* (i.e. values that will pass validation).
*/
attr.bp_addr = 0;
attr.bp_len = HW_BREAKPOINT_LEN_4;
attr.bp_type = type;
attr.disabled = 1;
bp = register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL, tsk);
if (IS_ERR(bp))
return bp;
err = ptrace_hbp_set_event(note_type, tsk, idx, bp);
if (err)
return ERR_PTR(err);
return bp;
}
static int ptrace_hbp_fill_attr_ctrl(unsigned int note_type,
struct arch_hw_breakpoint_ctrl ctrl,
struct perf_event_attr *attr)
{
int err, len, type, offset, disabled = !ctrl.enabled;
attr->disabled = disabled;
if (disabled)
return 0;
err = arch_bp_generic_fields(ctrl, &len, &type, &offset);
if (err)
return err;
switch (note_type) {
case NT_ARM_HW_BREAK:
if ((type & HW_BREAKPOINT_X) != type)
return -EINVAL;
break;
case NT_ARM_HW_WATCH:
if ((type & HW_BREAKPOINT_RW) != type)
return -EINVAL;
break;
default:
return -EINVAL;
}
attr->bp_len = len;
attr->bp_type = type;
attr->bp_addr += offset;
return 0;
}
static int ptrace_hbp_get_resource_info(unsigned int note_type, u32 *info)
{
u8 num;
u32 reg = 0;
switch (note_type) {
case NT_ARM_HW_BREAK:
num = hw_breakpoint_slots(TYPE_INST);
break;
case NT_ARM_HW_WATCH:
num = hw_breakpoint_slots(TYPE_DATA);
break;
default:
return -EINVAL;
}
reg |= debug_monitors_arch();
reg <<= 8;
reg |= num;
*info = reg;
return 0;
}
static int ptrace_hbp_get_ctrl(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx,
u32 *ctrl)
{
struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
if (IS_ERR(bp))
return PTR_ERR(bp);
*ctrl = bp ? encode_ctrl_reg(counter_arch_bp(bp)->ctrl) : 0;
return 0;
}
static int ptrace_hbp_get_addr(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx,
u64 *addr)
{
struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
if (IS_ERR(bp))
return PTR_ERR(bp);
*addr = bp ? counter_arch_bp(bp)->address : 0;
return 0;
}
static struct perf_event *ptrace_hbp_get_initialised_bp(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx)
{
struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
if (!bp)
bp = ptrace_hbp_create(note_type, tsk, idx);
return bp;
}
static int ptrace_hbp_set_ctrl(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx,
u32 uctrl)
{
int err;
struct perf_event *bp;
struct perf_event_attr attr;
struct arch_hw_breakpoint_ctrl ctrl;
bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
if (IS_ERR(bp)) {
err = PTR_ERR(bp);
return err;
}
attr = bp->attr;
decode_ctrl_reg(uctrl, &ctrl);
err = ptrace_hbp_fill_attr_ctrl(note_type, ctrl, &attr);
if (err)
return err;
return modify_user_hw_breakpoint(bp, &attr);
}
static int ptrace_hbp_set_addr(unsigned int note_type,
struct task_struct *tsk,
unsigned long idx,
u64 addr)
{
int err;
struct perf_event *bp;
struct perf_event_attr attr;
bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
if (IS_ERR(bp)) {
err = PTR_ERR(bp);
return err;
}
attr = bp->attr;
attr.bp_addr = addr;
err = modify_user_hw_breakpoint(bp, &attr);
return err;
}
#define PTRACE_HBP_ADDR_SZ sizeof(u64)
#define PTRACE_HBP_CTRL_SZ sizeof(u32)
#define PTRACE_HBP_PAD_SZ sizeof(u32)
static int hw_break_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
unsigned int note_type = regset->core_note_type;
int ret, idx = 0;
u32 info, ctrl;
u64 addr;
/* Resource info */
ret = ptrace_hbp_get_resource_info(note_type, &info);
if (ret)
return ret;
membuf_write(&to, &info, sizeof(info));
membuf_zero(&to, sizeof(u32));
/* (address, ctrl) registers */
while (to.left) {
ret = ptrace_hbp_get_addr(note_type, target, idx, &addr);
if (ret)
return ret;
ret = ptrace_hbp_get_ctrl(note_type, target, idx, &ctrl);
if (ret)
return ret;
membuf_store(&to, addr);
membuf_store(&to, ctrl);
membuf_zero(&to, sizeof(u32));
idx++;
}
return 0;
}
static int hw_break_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
unsigned int note_type = regset->core_note_type;
int ret, idx = 0, offset, limit;
u32 ctrl;
u64 addr;
/* Resource info and pad */
offset = offsetof(struct user_hwdebug_state, dbg_regs);
ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, offset);
if (ret)
return ret;
/* (address, ctrl) registers */
limit = regset->n * regset->size;
while (count && offset < limit) {
if (count < PTRACE_HBP_ADDR_SZ)
return -EINVAL;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
offset, offset + PTRACE_HBP_ADDR_SZ);
if (ret)
return ret;
ret = ptrace_hbp_set_addr(note_type, target, idx, addr);
if (ret)
return ret;
offset += PTRACE_HBP_ADDR_SZ;
if (!count)
break;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl,
offset, offset + PTRACE_HBP_CTRL_SZ);
if (ret)
return ret;
ret = ptrace_hbp_set_ctrl(note_type, target, idx, ctrl);
if (ret)
return ret;
offset += PTRACE_HBP_CTRL_SZ;
ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
offset,
offset + PTRACE_HBP_PAD_SZ);
if (ret)
return ret;
offset += PTRACE_HBP_PAD_SZ;
idx++;
}
return 0;
}
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
static int gpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
return membuf_write(&to, uregs, sizeof(*uregs));
}
static int gpr_set(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
struct user_pt_regs newregs = task_pt_regs(target)->user_regs;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
if (ret)
return ret;
if (!valid_user_regs(&newregs, target))
return -EINVAL;
task_pt_regs(target)->user_regs = newregs;
return 0;
}
static int fpr_active(struct task_struct *target, const struct user_regset *regset)
{
if (!system_supports_fpsimd())
return -ENODEV;
return regset->n;
}
/*
* TODO: update fp accessors for lazy context switching (sync/flush hwstate)
*/
static int __fpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct user_fpsimd_state *uregs;
sve_sync_to_fpsimd(target);
uregs = &target->thread.uw.fpsimd_state;
return membuf_write(&to, uregs, sizeof(*uregs));
}
static int fpr_get(struct task_struct *target, const struct user_regset *regset,
struct membuf to)
{
if (!system_supports_fpsimd())
return -EINVAL;
if (target == current)
fpsimd_preserve_current_state();
return __fpr_get(target, regset, to);
}
static int __fpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf,
unsigned int start_pos)
{
int ret;
struct user_fpsimd_state newstate;
/*
* Ensure target->thread.uw.fpsimd_state is up to date, so that a
* short copyin can't resurrect stale data.
*/
sve_sync_to_fpsimd(target);
newstate = target->thread.uw.fpsimd_state;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate,
start_pos, start_pos + sizeof(newstate));
if (ret)
return ret;
target->thread.uw.fpsimd_state = newstate;
return ret;
}
static int fpr_set(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
if (!system_supports_fpsimd())
return -EINVAL;
ret = __fpr_set(target, regset, pos, count, kbuf, ubuf, 0);
if (ret)
return ret;
sve_sync_from_fpsimd_zeropad(target);
fpsimd_flush_task_state(target);
return ret;
}
static int tls_get(struct task_struct *target, const struct user_regset *regset,
struct membuf to)
{
if (target == current)
tls_preserve_current_state();
return membuf_store(&to, target->thread.uw.tp_value);
}
static int tls_set(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
unsigned long tls = target->thread.uw.tp_value;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
if (ret)
return ret;
target->thread.uw.tp_value = tls;
return ret;
}
static int system_call_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
return membuf_store(&to, task_pt_regs(target)->syscallno);
}
static int system_call_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int syscallno = task_pt_regs(target)->syscallno;
int ret;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1);
if (ret)
return ret;
task_pt_regs(target)->syscallno = syscallno;
return ret;
}
#ifdef CONFIG_ARM64_SVE
static void sve_init_header_from_task(struct user_sve_header *header,
struct task_struct *target)
{
unsigned int vq;
memset(header, 0, sizeof(*header));
header->flags = test_tsk_thread_flag(target, TIF_SVE) ?
SVE_PT_REGS_SVE : SVE_PT_REGS_FPSIMD;
if (test_tsk_thread_flag(target, TIF_SVE_VL_INHERIT))
header->flags |= SVE_PT_VL_INHERIT;
header->vl = target->thread.sve_vl;
vq = sve_vq_from_vl(header->vl);
header->max_vl = sve_max_vl;
header->size = SVE_PT_SIZE(vq, header->flags);
header->max_size = SVE_PT_SIZE(sve_vq_from_vl(header->max_vl),
SVE_PT_REGS_SVE);
}
static unsigned int sve_size_from_header(struct user_sve_header const *header)
{
return ALIGN(header->size, SVE_VQ_BYTES);
}
static int sve_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct user_sve_header header;
unsigned int vq;
unsigned long start, end;
if (!system_supports_sve())
return -EINVAL;
/* Header */
sve_init_header_from_task(&header, target);
vq = sve_vq_from_vl(header.vl);
membuf_write(&to, &header, sizeof(header));
if (target == current)
fpsimd_preserve_current_state();
/* Registers: FPSIMD-only case */
BUILD_BUG_ON(SVE_PT_FPSIMD_OFFSET != sizeof(header));
if ((header.flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD)
return __fpr_get(target, regset, to);
/* Otherwise: full SVE case */
BUILD_BUG_ON(SVE_PT_SVE_OFFSET != sizeof(header));
start = SVE_PT_SVE_OFFSET;
end = SVE_PT_SVE_FFR_OFFSET(vq) + SVE_PT_SVE_FFR_SIZE(vq);
membuf_write(&to, target->thread.sve_state, end - start);
start = end;
end = SVE_PT_SVE_FPSR_OFFSET(vq);
membuf_zero(&to, end - start);
/*
* Copy fpsr, and fpcr which must follow contiguously in
* struct fpsimd_state:
*/
start = end;
end = SVE_PT_SVE_FPCR_OFFSET(vq) + SVE_PT_SVE_FPCR_SIZE;
membuf_write(&to, &target->thread.uw.fpsimd_state.fpsr, end - start);
start = end;
end = sve_size_from_header(&header);
return membuf_zero(&to, end - start);
}
static int sve_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
struct user_sve_header header;
unsigned int vq;
unsigned long start, end;
if (!system_supports_sve())
return -EINVAL;
/* Header */
if (count < sizeof(header))
return -EINVAL;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &header,
0, sizeof(header));
if (ret)
goto out;
/*
* Apart from SVE_PT_REGS_MASK, all SVE_PT_* flags are consumed by
* sve_set_vector_length(), which will also validate them for us:
*/
ret = sve_set_vector_length(target, header.vl,
((unsigned long)header.flags & ~SVE_PT_REGS_MASK) << 16);
if (ret)
goto out;
/* Actual VL set may be less than the user asked for: */
vq = sve_vq_from_vl(target->thread.sve_vl);
/* Registers: FPSIMD-only case */
BUILD_BUG_ON(SVE_PT_FPSIMD_OFFSET != sizeof(header));
if ((header.flags & SVE_PT_REGS_MASK) == SVE_PT_REGS_FPSIMD) {
ret = __fpr_set(target, regset, pos, count, kbuf, ubuf,
SVE_PT_FPSIMD_OFFSET);
clear_tsk_thread_flag(target, TIF_SVE);
goto out;
}
/* Otherwise: full SVE case */
/*
* If setting a different VL from the requested VL and there is
* register data, the data layout will be wrong: don't even
* try to set the registers in this case.
*/
if (count && vq != sve_vq_from_vl(header.vl)) {
ret = -EIO;
goto out;
}
sve_alloc(target);
/*
* Ensure target->thread.sve_state is up to date with target's
* FPSIMD regs, so that a short copyin leaves trailing registers
* unmodified.
*/
fpsimd_sync_to_sve(target);
set_tsk_thread_flag(target, TIF_SVE);
BUILD_BUG_ON(SVE_PT_SVE_OFFSET != sizeof(header));
start = SVE_PT_SVE_OFFSET;
end = SVE_PT_SVE_FFR_OFFSET(vq) + SVE_PT_SVE_FFR_SIZE(vq);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
target->thread.sve_state,
start, end);
if (ret)
goto out;
start = end;
end = SVE_PT_SVE_FPSR_OFFSET(vq);
ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
start, end);
if (ret)
goto out;
/*
* Copy fpsr, and fpcr which must follow contiguously in
* struct fpsimd_state:
*/
start = end;
end = SVE_PT_SVE_FPCR_OFFSET(vq) + SVE_PT_SVE_FPCR_SIZE;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&target->thread.uw.fpsimd_state.fpsr,
start, end);
out:
fpsimd_flush_task_state(target);
return ret;
}
#endif /* CONFIG_ARM64_SVE */
#ifdef CONFIG_ARM64_PTR_AUTH
static int pac_mask_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
/*
* The PAC bits can differ across data and instruction pointers
* depending on TCR_EL1.TBID*, which we may make use of in future, so
* we expose separate masks.
*/
unsigned long mask = ptrauth_user_pac_mask();
struct user_pac_mask uregs = {
.data_mask = mask,
.insn_mask = mask,
};
if (!system_supports_address_auth())
return -EINVAL;
return membuf_write(&to, &uregs, sizeof(uregs));
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static __uint128_t pac_key_to_user(const struct ptrauth_key *key)
{
return (__uint128_t)key->hi << 64 | key->lo;
}
static struct ptrauth_key pac_key_from_user(__uint128_t ukey)
{
struct ptrauth_key key = {
.lo = (unsigned long)ukey,
.hi = (unsigned long)(ukey >> 64),
};
return key;
}
static void pac_address_keys_to_user(struct user_pac_address_keys *ukeys,
const struct ptrauth_keys_user *keys)
{
ukeys->apiakey = pac_key_to_user(&keys->apia);
ukeys->apibkey = pac_key_to_user(&keys->apib);
ukeys->apdakey = pac_key_to_user(&keys->apda);
ukeys->apdbkey = pac_key_to_user(&keys->apdb);
}
static void pac_address_keys_from_user(struct ptrauth_keys_user *keys,
const struct user_pac_address_keys *ukeys)
{
keys->apia = pac_key_from_user(ukeys->apiakey);
keys->apib = pac_key_from_user(ukeys->apibkey);
keys->apda = pac_key_from_user(ukeys->apdakey);
keys->apdb = pac_key_from_user(ukeys->apdbkey);
}
static int pac_address_keys_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct ptrauth_keys_user *keys = &target->thread.keys_user;
struct user_pac_address_keys user_keys;
if (!system_supports_address_auth())
return -EINVAL;
pac_address_keys_to_user(&user_keys, keys);
return membuf_write(&to, &user_keys, sizeof(user_keys));
}
static int pac_address_keys_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct ptrauth_keys_user *keys = &target->thread.keys_user;
struct user_pac_address_keys user_keys;
int ret;
if (!system_supports_address_auth())
return -EINVAL;
pac_address_keys_to_user(&user_keys, keys);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&user_keys, 0, -1);
if (ret)
return ret;
pac_address_keys_from_user(keys, &user_keys);
return 0;
}
static void pac_generic_keys_to_user(struct user_pac_generic_keys *ukeys,
const struct ptrauth_keys_user *keys)
{
ukeys->apgakey = pac_key_to_user(&keys->apga);
}
static void pac_generic_keys_from_user(struct ptrauth_keys_user *keys,
const struct user_pac_generic_keys *ukeys)
{
keys->apga = pac_key_from_user(ukeys->apgakey);
}
static int pac_generic_keys_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct ptrauth_keys_user *keys = &target->thread.keys_user;
struct user_pac_generic_keys user_keys;
if (!system_supports_generic_auth())
return -EINVAL;
pac_generic_keys_to_user(&user_keys, keys);
return membuf_write(&to, &user_keys, sizeof(user_keys));
}
static int pac_generic_keys_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct ptrauth_keys_user *keys = &target->thread.keys_user;
struct user_pac_generic_keys user_keys;
int ret;
if (!system_supports_generic_auth())
return -EINVAL;
pac_generic_keys_to_user(&user_keys, keys);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&user_keys, 0, -1);
if (ret)
return ret;
pac_generic_keys_from_user(keys, &user_keys);
return 0;
}
#endif /* CONFIG_CHECKPOINT_RESTORE */
#endif /* CONFIG_ARM64_PTR_AUTH */
enum aarch64_regset {
REGSET_GPR,
REGSET_FPR,
REGSET_TLS,
#ifdef CONFIG_HAVE_HW_BREAKPOINT
REGSET_HW_BREAK,
REGSET_HW_WATCH,
#endif
REGSET_SYSTEM_CALL,
#ifdef CONFIG_ARM64_SVE
REGSET_SVE,
#endif
#ifdef CONFIG_ARM64_PTR_AUTH
REGSET_PAC_MASK,
#ifdef CONFIG_CHECKPOINT_RESTORE
REGSET_PACA_KEYS,
REGSET_PACG_KEYS,
#endif
#endif
};
static const struct user_regset aarch64_regsets[] = {
[REGSET_GPR] = {
.core_note_type = NT_PRSTATUS,
.n = sizeof(struct user_pt_regs) / sizeof(u64),
.size = sizeof(u64),
.align = sizeof(u64),
.regset_get = gpr_get,
.set = gpr_set
},
[REGSET_FPR] = {
.core_note_type = NT_PRFPREG,
.n = sizeof(struct user_fpsimd_state) / sizeof(u32),
/*
* We pretend we have 32-bit registers because the fpsr and
* fpcr are 32-bits wide.
*/
.size = sizeof(u32),
.align = sizeof(u32),
.active = fpr_active,
.regset_get = fpr_get,
.set = fpr_set
},
[REGSET_TLS] = {
.core_note_type = NT_ARM_TLS,
.n = 1,
.size = sizeof(void *),
.align = sizeof(void *),
.regset_get = tls_get,
.set = tls_set,
},
#ifdef CONFIG_HAVE_HW_BREAKPOINT
[REGSET_HW_BREAK] = {
.core_note_type = NT_ARM_HW_BREAK,
.n = sizeof(struct user_hwdebug_state) / sizeof(u32),
.size = sizeof(u32),
.align = sizeof(u32),
.regset_get = hw_break_get,
.set = hw_break_set,
},
[REGSET_HW_WATCH] = {
.core_note_type = NT_ARM_HW_WATCH,
.n = sizeof(struct user_hwdebug_state) / sizeof(u32),
.size = sizeof(u32),
.align = sizeof(u32),
.regset_get = hw_break_get,
.set = hw_break_set,
},
#endif
[REGSET_SYSTEM_CALL] = {
.core_note_type = NT_ARM_SYSTEM_CALL,
.n = 1,
.size = sizeof(int),
.align = sizeof(int),
.regset_get = system_call_get,
.set = system_call_set,
},
#ifdef CONFIG_ARM64_SVE
[REGSET_SVE] = { /* Scalable Vector Extension */
.core_note_type = NT_ARM_SVE,
.n = DIV_ROUND_UP(SVE_PT_SIZE(SVE_VQ_MAX, SVE_PT_REGS_SVE),
SVE_VQ_BYTES),
.size = SVE_VQ_BYTES,
.align = SVE_VQ_BYTES,
.regset_get = sve_get,
.set = sve_set,
},
#endif
#ifdef CONFIG_ARM64_PTR_AUTH
[REGSET_PAC_MASK] = {
.core_note_type = NT_ARM_PAC_MASK,
.n = sizeof(struct user_pac_mask) / sizeof(u64),
.size = sizeof(u64),
.align = sizeof(u64),
.regset_get = pac_mask_get,
/* this cannot be set dynamically */
},
#ifdef CONFIG_CHECKPOINT_RESTORE
[REGSET_PACA_KEYS] = {
.core_note_type = NT_ARM_PACA_KEYS,
.n = sizeof(struct user_pac_address_keys) / sizeof(__uint128_t),
.size = sizeof(__uint128_t),
.align = sizeof(__uint128_t),
.regset_get = pac_address_keys_get,
.set = pac_address_keys_set,
},
[REGSET_PACG_KEYS] = {
.core_note_type = NT_ARM_PACG_KEYS,
.n = sizeof(struct user_pac_generic_keys) / sizeof(__uint128_t),
.size = sizeof(__uint128_t),
.align = sizeof(__uint128_t),
.regset_get = pac_generic_keys_get,
.set = pac_generic_keys_set,
},
#endif
#endif
};
static const struct user_regset_view user_aarch64_view = {
.name = "aarch64", .e_machine = EM_AARCH64,
.regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
};
#ifdef CONFIG_COMPAT
enum compat_regset {
REGSET_COMPAT_GPR,
REGSET_COMPAT_VFP,
};
static inline compat_ulong_t compat_get_user_reg(struct task_struct *task, int idx)
{
struct pt_regs *regs = task_pt_regs(task);
switch (idx) {
case 15:
return regs->pc;
case 16:
return pstate_to_compat_psr(regs->pstate);
case 17:
return regs->orig_x0;
default:
return regs->regs[idx];
}
}
static int compat_gpr_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
int i = 0;
while (to.left)
membuf_store(&to, compat_get_user_reg(target, i++));
return 0;
}
static int compat_gpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct pt_regs newregs;
int ret = 0;
unsigned int i, start, num_regs;
/* Calculate the number of AArch32 registers contained in count */
num_regs = count / regset->size;
/* Convert pos into an register number */
start = pos / regset->size;
if (start + num_regs > regset->n)
return -EIO;
newregs = *task_pt_regs(target);
for (i = 0; i < num_regs; ++i) {
unsigned int idx = start + i;
compat_ulong_t reg;
if (kbuf) {
memcpy(&reg, kbuf, sizeof(reg));
kbuf += sizeof(reg);
} else {
ret = copy_from_user(&reg, ubuf, sizeof(reg));
if (ret) {
ret = -EFAULT;
break;
}
ubuf += sizeof(reg);
}
switch (idx) {
case 15:
newregs.pc = reg;
break;
case 16:
reg = compat_psr_to_pstate(reg);
newregs.pstate = reg;
break;
case 17:
newregs.orig_x0 = reg;
break;
default:
newregs.regs[idx] = reg;
}
}
if (valid_user_regs(&newregs.user_regs, target))
*task_pt_regs(target) = newregs;
else
ret = -EINVAL;
return ret;
}
static int compat_vfp_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
struct user_fpsimd_state *uregs;
compat_ulong_t fpscr;
if (!system_supports_fpsimd())
return -EINVAL;
uregs = &target->thread.uw.fpsimd_state;
if (target == current)
fpsimd_preserve_current_state();
/*
* The VFP registers are packed into the fpsimd_state, so they all sit
* nicely together for us. We just need to create the fpscr separately.
*/
membuf_write(&to, uregs, VFP_STATE_SIZE - sizeof(compat_ulong_t));
fpscr = (uregs->fpsr & VFP_FPSCR_STAT_MASK) |
(uregs->fpcr & VFP_FPSCR_CTRL_MASK);
return membuf_store(&to, fpscr);
}
static int compat_vfp_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct user_fpsimd_state *uregs;
compat_ulong_t fpscr;
int ret, vregs_end_pos;
if (!system_supports_fpsimd())
return -EINVAL;
uregs = &target->thread.uw.fpsimd_state;
vregs_end_pos = VFP_STATE_SIZE - sizeof(compat_ulong_t);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
vregs_end_pos);
if (count && !ret) {
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &fpscr,
vregs_end_pos, VFP_STATE_SIZE);
if (!ret) {
uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
}
}
fpsimd_flush_task_state(target);
return ret;
}
static int compat_tls_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
return membuf_store(&to, (compat_ulong_t)target->thread.uw.tp_value);
}
static int compat_tls_set(struct task_struct *target,
const struct user_regset *regset, unsigned int pos,
unsigned int count, const void *kbuf,
const void __user *ubuf)
{
int ret;
compat_ulong_t tls = target->thread.uw.tp_value;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
if (ret)
return ret;
target->thread.uw.tp_value = tls;
return ret;
}
static const struct user_regset aarch32_regsets[] = {
[REGSET_COMPAT_GPR] = {
.core_note_type = NT_PRSTATUS,
.n = COMPAT_ELF_NGREG,
.size = sizeof(compat_elf_greg_t),
.align = sizeof(compat_elf_greg_t),
.regset_get = compat_gpr_get,
.set = compat_gpr_set
},
[REGSET_COMPAT_VFP] = {
.core_note_type = NT_ARM_VFP,
.n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
.size = sizeof(compat_ulong_t),
.align = sizeof(compat_ulong_t),
.active = fpr_active,
.regset_get = compat_vfp_get,
.set = compat_vfp_set
},
};
static const struct user_regset_view user_aarch32_view = {
.name = "aarch32", .e_machine = EM_ARM,
.regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets)
};
static const struct user_regset aarch32_ptrace_regsets[] = {
[REGSET_GPR] = {
.core_note_type = NT_PRSTATUS,
.n = COMPAT_ELF_NGREG,
.size = sizeof(compat_elf_greg_t),
.align = sizeof(compat_elf_greg_t),
.regset_get = compat_gpr_get,
.set = compat_gpr_set
},
[REGSET_FPR] = {
.core_note_type = NT_ARM_VFP,
.n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
.size = sizeof(compat_ulong_t),
.align = sizeof(compat_ulong_t),
.regset_get = compat_vfp_get,
.set = compat_vfp_set
},
[REGSET_TLS] = {
.core_note_type = NT_ARM_TLS,
.n = 1,
.size = sizeof(compat_ulong_t),
.align = sizeof(compat_ulong_t),
.regset_get = compat_tls_get,
.set = compat_tls_set,
},
#ifdef CONFIG_HAVE_HW_BREAKPOINT
[REGSET_HW_BREAK] = {
.core_note_type = NT_ARM_HW_BREAK,
.n = sizeof(struct user_hwdebug_state) / sizeof(u32),
.size = sizeof(u32),
.align = sizeof(u32),
.regset_get = hw_break_get,
.set = hw_break_set,
},
[REGSET_HW_WATCH] = {
.core_note_type = NT_ARM_HW_WATCH,
.n = sizeof(struct user_hwdebug_state) / sizeof(u32),
.size = sizeof(u32),
.align = sizeof(u32),
.regset_get = hw_break_get,
.set = hw_break_set,
},
#endif
[REGSET_SYSTEM_CALL] = {
.core_note_type = NT_ARM_SYSTEM_CALL,
.n = 1,
.size = sizeof(int),
.align = sizeof(int),
.regset_get = system_call_get,
.set = system_call_set,
},
};
static const struct user_regset_view user_aarch32_ptrace_view = {
.name = "aarch32", .e_machine = EM_ARM,
.regsets = aarch32_ptrace_regsets, .n = ARRAY_SIZE(aarch32_ptrace_regsets)
};
static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
compat_ulong_t __user *ret)
{
compat_ulong_t tmp;
if (off & 3)
return -EIO;
if (off == COMPAT_PT_TEXT_ADDR)
tmp = tsk->mm->start_code;
else if (off == COMPAT_PT_DATA_ADDR)
tmp = tsk->mm->start_data;
else if (off == COMPAT_PT_TEXT_END_ADDR)
tmp = tsk->mm->end_code;
else if (off < sizeof(compat_elf_gregset_t))
tmp = compat_get_user_reg(tsk, off >> 2);
else if (off >= COMPAT_USER_SZ)
return -EIO;
else
tmp = 0;
return put_user(tmp, ret);
}
static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
compat_ulong_t val)
{
struct pt_regs newregs = *task_pt_regs(tsk);
unsigned int idx = off / 4;
if (off & 3 || off >= COMPAT_USER_SZ)
return -EIO;
if (off >= sizeof(compat_elf_gregset_t))
return 0;
switch (idx) {
case 15:
newregs.pc = val;
break;
case 16:
newregs.pstate = compat_psr_to_pstate(val);
break;
case 17:
newregs.orig_x0 = val;
break;
default:
newregs.regs[idx] = val;
}
if (!valid_user_regs(&newregs.user_regs, tsk))
return -EINVAL;
*task_pt_regs(tsk) = newregs;
return 0;
}
#ifdef CONFIG_HAVE_HW_BREAKPOINT
/*
* Convert a virtual register number into an index for a thread_info
* breakpoint array. Breakpoints are identified using positive numbers
* whilst watchpoints are negative. The registers are laid out as pairs
* of (address, control), each pair mapping to a unique hw_breakpoint struct.
* Register 0 is reserved for describing resource information.
*/
static int compat_ptrace_hbp_num_to_idx(compat_long_t num)
{
return (abs(num) - 1) >> 1;
}
static int compat_ptrace_hbp_get_resource_info(u32 *kdata)
{
u8 num_brps, num_wrps, debug_arch, wp_len;
u32 reg = 0;
num_brps = hw_breakpoint_slots(TYPE_INST);
num_wrps = hw_breakpoint_slots(TYPE_DATA);
debug_arch = debug_monitors_arch();
wp_len = 8;
reg |= debug_arch;
reg <<= 8;
reg |= wp_len;
reg <<= 8;
reg |= num_wrps;
reg <<= 8;
reg |= num_brps;
*kdata = reg;
return 0;
}
static int compat_ptrace_hbp_get(unsigned int note_type,
struct task_struct *tsk,
compat_long_t num,
u32 *kdata)
{
u64 addr = 0;
u32 ctrl = 0;
int err, idx = compat_ptrace_hbp_num_to_idx(num);
if (num & 1) {
err = ptrace_hbp_get_addr(note_type, tsk, idx, &addr);
*kdata = (u32)addr;
} else {
err = ptrace_hbp_get_ctrl(note_type, tsk, idx, &ctrl);
*kdata = ctrl;
}
return err;
}
static int compat_ptrace_hbp_set(unsigned int note_type,
struct task_struct *tsk,
compat_long_t num,
u32 *kdata)
{
u64 addr;
u32 ctrl;
int err, idx = compat_ptrace_hbp_num_to_idx(num);
if (num & 1) {
addr = *kdata;
err = ptrace_hbp_set_addr(note_type, tsk, idx, addr);
} else {
ctrl = *kdata;
err = ptrace_hbp_set_ctrl(note_type, tsk, idx, ctrl);
}
return err;
}
static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
compat_ulong_t __user *data)
{
int ret;
u32 kdata;
/* Watchpoint */
if (num < 0) {
ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
/* Resource info */
} else if (num == 0) {
ret = compat_ptrace_hbp_get_resource_info(&kdata);
/* Breakpoint */
} else {
ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
}
if (!ret)
ret = put_user(kdata, data);
return ret;
}
static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
compat_ulong_t __user *data)
{
int ret;
u32 kdata = 0;
if (num == 0)
return 0;
ret = get_user(kdata, data);
if (ret)
return ret;
if (num < 0)
ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
else
ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
return ret;
}
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
compat_ulong_t caddr, compat_ulong_t cdata)
{
unsigned long addr = caddr;
unsigned long data = cdata;
void __user *datap = compat_ptr(data);
int ret;
switch (request) {
case PTRACE_PEEKUSR:
ret = compat_ptrace_read_user(child, addr, datap);
break;
case PTRACE_POKEUSR:
ret = compat_ptrace_write_user(child, addr, data);
break;
case COMPAT_PTRACE_GETREGS:
ret = copy_regset_to_user(child,
&user_aarch32_view,
REGSET_COMPAT_GPR,
0, sizeof(compat_elf_gregset_t),
datap);
break;
case COMPAT_PTRACE_SETREGS:
ret = copy_regset_from_user(child,
&user_aarch32_view,
REGSET_COMPAT_GPR,
0, sizeof(compat_elf_gregset_t),
datap);
break;
case COMPAT_PTRACE_GET_THREAD_AREA:
ret = put_user((compat_ulong_t)child->thread.uw.tp_value,
(compat_ulong_t __user *)datap);
break;
case COMPAT_PTRACE_SET_SYSCALL:
task_pt_regs(child)->syscallno = data;
ret = 0;
break;
case COMPAT_PTRACE_GETVFPREGS:
ret = copy_regset_to_user(child,
&user_aarch32_view,
REGSET_COMPAT_VFP,
0, VFP_STATE_SIZE,
datap);
break;
case COMPAT_PTRACE_SETVFPREGS:
ret = copy_regset_from_user(child,
&user_aarch32_view,
REGSET_COMPAT_VFP,
0, VFP_STATE_SIZE,
datap);
break;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
case COMPAT_PTRACE_GETHBPREGS:
ret = compat_ptrace_gethbpregs(child, addr, datap);
break;
case COMPAT_PTRACE_SETHBPREGS:
ret = compat_ptrace_sethbpregs(child, addr, datap);
break;
#endif
default:
ret = compat_ptrace_request(child, request, addr,
data);
break;
}
return ret;
}
#endif /* CONFIG_COMPAT */
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_COMPAT
/*
* Core dumping of 32-bit tasks or compat ptrace requests must use the
* user_aarch32_view compatible with arm32. Native ptrace requests on
* 32-bit children use an extended user_aarch32_ptrace_view to allow
* access to the TLS register.
*/
if (is_compat_task())
return &user_aarch32_view;
else if (is_compat_thread(task_thread_info(task)))
return &user_aarch32_ptrace_view;
#endif
return &user_aarch64_view;
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
return ptrace_request(child, request, addr, data);
}
enum ptrace_syscall_dir {
PTRACE_SYSCALL_ENTER = 0,
PTRACE_SYSCALL_EXIT,
};
static void tracehook_report_syscall(struct pt_regs *regs,
enum ptrace_syscall_dir dir)
{
int regno;
unsigned long saved_reg;
/*
* We have some ABI weirdness here in the way that we handle syscall
* exit stops because we indicate whether or not the stop has been
* signalled from syscall entry or syscall exit by clobbering a general
* purpose register (ip/r12 for AArch32, x7 for AArch64) in the tracee
* and restoring its old value after the stop. This means that:
*
* - Any writes by the tracer to this register during the stop are
* ignored/discarded.
*
* - The actual value of the register is not available during the stop,
* so the tracer cannot save it and restore it later.
*
* - Syscall stops behave differently to seccomp and pseudo-step traps
* (the latter do not nobble any registers).
*/
regno = (is_compat_task() ? 12 : 7);
saved_reg = regs->regs[regno];
regs->regs[regno] = dir;
if (dir == PTRACE_SYSCALL_ENTER) {
if (tracehook_report_syscall_entry(regs))
forget_syscall(regs);
regs->regs[regno] = saved_reg;
} else if (!test_thread_flag(TIF_SINGLESTEP)) {
tracehook_report_syscall_exit(regs, 0);
regs->regs[regno] = saved_reg;
} else {
regs->regs[regno] = saved_reg;
/*
* Signal a pseudo-step exception since we are stepping but
* tracer modifications to the registers may have rewound the
* state machine.
*/
tracehook_report_syscall_exit(regs, 1);
}
}
int syscall_trace_enter(struct pt_regs *regs)
{
unsigned long flags = READ_ONCE(current_thread_info()->flags);
if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) {
tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
if (!in_syscall(regs) || (flags & _TIF_SYSCALL_EMU))
return NO_SYSCALL;
}
/* Do the secure computing after ptrace; failures should be fast. */
if (secure_computing() == -1)
return NO_SYSCALL;
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_enter(regs, regs->syscallno);
audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
regs->regs[2], regs->regs[3]);
return regs->syscallno;
}
void syscall_trace_exit(struct pt_regs *regs)
{
unsigned long flags = READ_ONCE(current_thread_info()->flags);
audit_syscall_exit(regs);
if (flags & _TIF_SYSCALL_TRACEPOINT)
trace_sys_exit(regs, regs_return_value(regs));
if (flags & (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP))
tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
rseq_syscall(regs);
}
/*
* SPSR_ELx bits which are always architecturally RES0 per ARM DDI 0487D.a.
* We permit userspace to set SSBS (AArch64 bit 12, AArch32 bit 23) which is
* not described in ARM DDI 0487D.a.
* We treat PAN and UAO as RES0 bits, as they are meaningless at EL0, and may
* be allocated an EL0 meaning in future.
* Userspace cannot use these until they have an architectural meaning.
* Note that this follows the SPSR_ELx format, not the AArch32 PSR format.
* We also reserve IL for the kernel; SS is handled dynamically.
*/
#define SPSR_EL1_AARCH64_RES0_BITS \
(GENMASK_ULL(63, 32) | GENMASK_ULL(27, 25) | GENMASK_ULL(23, 22) | \
GENMASK_ULL(20, 13) | GENMASK_ULL(5, 5))
#define SPSR_EL1_AARCH32_RES0_BITS \
(GENMASK_ULL(63, 32) | GENMASK_ULL(22, 22) | GENMASK_ULL(20, 20))
static int valid_compat_regs(struct user_pt_regs *regs)
{
regs->pstate &= ~SPSR_EL1_AARCH32_RES0_BITS;
if (!system_supports_mixed_endian_el0()) {
if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
regs->pstate |= PSR_AA32_E_BIT;
else
regs->pstate &= ~PSR_AA32_E_BIT;
}
if (user_mode(regs) && (regs->pstate & PSR_MODE32_BIT) &&
(regs->pstate & PSR_AA32_A_BIT) == 0 &&
(regs->pstate & PSR_AA32_I_BIT) == 0 &&
(regs->pstate & PSR_AA32_F_BIT) == 0) {
return 1;
}
/*
* Force PSR to a valid 32-bit EL0t, preserving the same bits as
* arch/arm.
*/
regs->pstate &= PSR_AA32_N_BIT | PSR_AA32_Z_BIT |
PSR_AA32_C_BIT | PSR_AA32_V_BIT |
PSR_AA32_Q_BIT | PSR_AA32_IT_MASK |
PSR_AA32_GE_MASK | PSR_AA32_E_BIT |
PSR_AA32_T_BIT;
regs->pstate |= PSR_MODE32_BIT;
return 0;
}
static int valid_native_regs(struct user_pt_regs *regs)
{
regs->pstate &= ~SPSR_EL1_AARCH64_RES0_BITS;
if (user_mode(regs) && !(regs->pstate & PSR_MODE32_BIT) &&
(regs->pstate & PSR_D_BIT) == 0 &&
(regs->pstate & PSR_A_BIT) == 0 &&
(regs->pstate & PSR_I_BIT) == 0 &&
(regs->pstate & PSR_F_BIT) == 0) {
return 1;
}
/* Force PSR to a valid 64-bit EL0t */
regs->pstate &= PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT;
return 0;
}
/*
* Are the current registers suitable for user mode? (used to maintain
* security in signal handlers)
*/
int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task)
{
/* https://lore.kernel.org/lkml/20191118131525.GA4180@willie-the-truck */
user_regs_reset_single_step(regs, task);
if (is_compat_thread(task_thread_info(task)))
return valid_compat_regs(regs);
else
return valid_native_regs(regs);
}
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