180 lines
4.9 KiB
C
180 lines
4.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/sched/task_stack.h>
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#include <linux/perf_event.h>
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#include <linux/bug.h>
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#include <linux/stddef.h>
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#include <asm/perf_regs.h>
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#include <asm/ptrace.h>
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#ifdef CONFIG_X86_32
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#define PERF_REG_X86_MAX PERF_REG_X86_32_MAX
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#else
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#define PERF_REG_X86_MAX PERF_REG_X86_64_MAX
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#endif
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#define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r)
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static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
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PT_REGS_OFFSET(PERF_REG_X86_AX, ax),
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PT_REGS_OFFSET(PERF_REG_X86_BX, bx),
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PT_REGS_OFFSET(PERF_REG_X86_CX, cx),
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PT_REGS_OFFSET(PERF_REG_X86_DX, dx),
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PT_REGS_OFFSET(PERF_REG_X86_SI, si),
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PT_REGS_OFFSET(PERF_REG_X86_DI, di),
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PT_REGS_OFFSET(PERF_REG_X86_BP, bp),
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PT_REGS_OFFSET(PERF_REG_X86_SP, sp),
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PT_REGS_OFFSET(PERF_REG_X86_IP, ip),
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PT_REGS_OFFSET(PERF_REG_X86_FLAGS, flags),
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PT_REGS_OFFSET(PERF_REG_X86_CS, cs),
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PT_REGS_OFFSET(PERF_REG_X86_SS, ss),
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#ifdef CONFIG_X86_32
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PT_REGS_OFFSET(PERF_REG_X86_DS, ds),
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PT_REGS_OFFSET(PERF_REG_X86_ES, es),
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PT_REGS_OFFSET(PERF_REG_X86_FS, fs),
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PT_REGS_OFFSET(PERF_REG_X86_GS, gs),
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#else
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/*
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* The pt_regs struct does not store
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* ds, es, fs, gs in 64 bit mode.
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*/
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(unsigned int) -1,
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(unsigned int) -1,
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(unsigned int) -1,
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(unsigned int) -1,
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#endif
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#ifdef CONFIG_X86_64
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PT_REGS_OFFSET(PERF_REG_X86_R8, r8),
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PT_REGS_OFFSET(PERF_REG_X86_R9, r9),
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PT_REGS_OFFSET(PERF_REG_X86_R10, r10),
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PT_REGS_OFFSET(PERF_REG_X86_R11, r11),
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PT_REGS_OFFSET(PERF_REG_X86_R12, r12),
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PT_REGS_OFFSET(PERF_REG_X86_R13, r13),
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PT_REGS_OFFSET(PERF_REG_X86_R14, r14),
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PT_REGS_OFFSET(PERF_REG_X86_R15, r15),
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#endif
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};
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u64 perf_reg_value(struct pt_regs *regs, int idx)
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{
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if (WARN_ON_ONCE(idx >= ARRAY_SIZE(pt_regs_offset)))
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return 0;
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return regs_get_register(regs, pt_regs_offset[idx]);
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}
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#define REG_RESERVED (~((1ULL << PERF_REG_X86_MAX) - 1ULL))
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#ifdef CONFIG_X86_32
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int perf_reg_validate(u64 mask)
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{
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if (!mask || mask & REG_RESERVED)
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return -EINVAL;
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return 0;
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}
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u64 perf_reg_abi(struct task_struct *task)
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{
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return PERF_SAMPLE_REGS_ABI_32;
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}
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void perf_get_regs_user(struct perf_regs *regs_user,
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struct pt_regs *regs,
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struct pt_regs *regs_user_copy)
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{
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regs_user->regs = task_pt_regs(current);
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regs_user->abi = perf_reg_abi(current);
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}
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#else /* CONFIG_X86_64 */
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#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \
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(1ULL << PERF_REG_X86_ES) | \
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(1ULL << PERF_REG_X86_FS) | \
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(1ULL << PERF_REG_X86_GS))
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int perf_reg_validate(u64 mask)
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{
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if (!mask || mask & REG_RESERVED)
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return -EINVAL;
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if (mask & REG_NOSUPPORT)
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return -EINVAL;
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return 0;
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}
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u64 perf_reg_abi(struct task_struct *task)
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{
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if (test_tsk_thread_flag(task, TIF_IA32))
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return PERF_SAMPLE_REGS_ABI_32;
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else
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return PERF_SAMPLE_REGS_ABI_64;
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}
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void perf_get_regs_user(struct perf_regs *regs_user,
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struct pt_regs *regs,
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struct pt_regs *regs_user_copy)
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{
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struct pt_regs *user_regs = task_pt_regs(current);
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/*
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* If we're in an NMI that interrupted task_pt_regs setup, then
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* we can't sample user regs at all. This check isn't really
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* sufficient, though, as we could be in an NMI inside an interrupt
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* that happened during task_pt_regs setup.
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*/
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if (regs->sp > (unsigned long)&user_regs->r11 &&
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regs->sp <= (unsigned long)(user_regs + 1)) {
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regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
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regs_user->regs = NULL;
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return;
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}
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/*
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* These registers are always saved on 64-bit syscall entry.
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* On 32-bit entry points, they are saved too except r8..r11.
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*/
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regs_user_copy->ip = user_regs->ip;
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regs_user_copy->ax = user_regs->ax;
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regs_user_copy->cx = user_regs->cx;
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regs_user_copy->dx = user_regs->dx;
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regs_user_copy->si = user_regs->si;
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regs_user_copy->di = user_regs->di;
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regs_user_copy->r8 = user_regs->r8;
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regs_user_copy->r9 = user_regs->r9;
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regs_user_copy->r10 = user_regs->r10;
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regs_user_copy->r11 = user_regs->r11;
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regs_user_copy->orig_ax = user_regs->orig_ax;
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regs_user_copy->flags = user_regs->flags;
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regs_user_copy->sp = user_regs->sp;
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regs_user_copy->cs = user_regs->cs;
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regs_user_copy->ss = user_regs->ss;
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/*
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* Store user space frame-pointer value on sample
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* to facilitate stack unwinding for cases when
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* user space executable code has such support
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* enabled at compile time:
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*/
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regs_user_copy->bp = user_regs->bp;
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regs_user_copy->bx = -1;
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regs_user_copy->r12 = -1;
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regs_user_copy->r13 = -1;
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regs_user_copy->r14 = -1;
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regs_user_copy->r15 = -1;
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/*
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* For this to be at all useful, we need a reasonable guess for
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* the ABI. Be careful: we're in NMI context, and we're
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* considering current to be the current task, so we should
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* be careful not to look at any other percpu variables that might
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* change during context switches.
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*/
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regs_user->abi = user_64bit_mode(user_regs) ?
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PERF_SAMPLE_REGS_ABI_64 : PERF_SAMPLE_REGS_ABI_32;
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regs_user->regs = regs_user_copy;
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}
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#endif /* CONFIG_X86_32 */
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