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selftests/vm/pkeys: introduce powerpc support 

This makes use of the abstractions added earlier and introduces support
for powerpc.

For powerpc, after receiving the SIGSEGV, the signal handler must
explicitly restore access permissions for the faulting pkey to allow the
test to continue.  As this makes use of pkey_access_allow(), all of its
dependencies and other similar functions have been moved ahead of the
signal handler.

[sandipan@linux.ibm.com: fix powerpc access right updates]
  Link: http://lkml.kernel.org/r/5f65cf37be993760de8112a88da194e3ccbb2bf8.1588959697.git.sandipan@linux.ibm.com
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "Desnes A. Nunes do Rosario" <desnesn@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Suchanek <msuchanek@suse.de>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/b121e9fd33789ed9195276e32fe4e80bb6b88a31.1585646528.git.sandipan@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ram Pai 2020-06-04 16:52:15 -07:00 committed by Linus Torvalds
parent 604c496b22
commit 589944b53b
3 changed files with 270 additions and 164 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
tools/testing/selftests/vm/pkey-helpers.h
View File

@ -79,6 +79,8 @@ void expected_pkey_fault(int pkey);
#if defined(__i386__) || defined(__x86_64__) /* arch */
#include "pkey-x86.h"
#elif defined(__powerpc64__) /* arch */
#include "pkey-powerpc.h"
#else /* arch */
#error Architecture not supported
#endif /* arch */

91
tools/testing/selftests/vm/pkey-powerpc.h Normal file
View File

@ -0,0 +1,91 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _PKEYS_POWERPC_H
#define _PKEYS_POWERPC_H
#ifndef SYS_mprotect_key
# define SYS_mprotect_key 386
#endif
#ifndef SYS_pkey_alloc
# define SYS_pkey_alloc 384
# define SYS_pkey_free 385
#endif
#define REG_IP_IDX PT_NIP
#define REG_TRAPNO PT_TRAP
#define gregs gp_regs
#define fpregs fp_regs
#define si_pkey_offset 0x20
#ifndef PKEY_DISABLE_ACCESS
# define PKEY_DISABLE_ACCESS 0x3 /* disable read and write */
#endif
#ifndef PKEY_DISABLE_WRITE
# define PKEY_DISABLE_WRITE 0x2
#endif
#define NR_PKEYS 32
#define NR_RESERVED_PKEYS_4K 27 /* pkey-0, pkey-1, exec-only-pkey
and 24 other keys that cannot be
represented in the PTE */
#define NR_RESERVED_PKEYS_64K 3 /* pkey-0, pkey-1 and exec-only-pkey */
#define PKEY_BITS_PER_PKEY 2
#define HPAGE_SIZE (1UL << 24)
#define PAGE_SIZE (1UL << 16)
static inline u32 pkey_bit_position(int pkey)
{
return (NR_PKEYS - pkey - 1) * PKEY_BITS_PER_PKEY;
}
static inline u64 __read_pkey_reg(void)
{
u64 pkey_reg;
asm volatile("mfspr %0, 0xd" : "=r" (pkey_reg));
return pkey_reg;
}
static inline void __write_pkey_reg(u64 pkey_reg)
{
u64 amr = pkey_reg;
dprintf4("%s() changing %016llx to %016llx\n",
__func__, __read_pkey_reg(), pkey_reg);
asm volatile("isync; mtspr 0xd, %0; isync"
: : "r" ((unsigned long)(amr)) : "memory");
dprintf4("%s() pkey register after changing %016llx to %016llx\n",
__func__, __read_pkey_reg(), pkey_reg);
}
static inline int cpu_has_pku(void)
{
return 1;
}
static inline int get_arch_reserved_keys(void)
{
if (sysconf(_SC_PAGESIZE) == 4096)
return NR_RESERVED_PKEYS_4K;
else
return NR_RESERVED_PKEYS_64K;
}
void expect_fault_on_read_execonly_key(void *p1, int pkey)
{
/*
* powerpc does not allow userspace to change permissions of exec-only
* keys since those keys are not allocated by userspace. The signal
* handler wont be able to reset the permissions, which means the code
* will infinitely continue to segfault here.
*/
return;
}
/* 4-byte instructions * 16384 = 64K page */
#define __page_o_noops() asm(".rept 16384 ; nop; .endr")
#endif /* _PKEYS_POWERPC_H */

341
tools/testing/selftests/vm/protection_keys.c
View File

@ -169,170 +169,6 @@ void dump_mem(void *dumpme, int len_bytes)
}
}
/* Failed address bound checks: */
#ifndef SEGV_BNDERR
# define SEGV_BNDERR 3
#endif
#ifndef SEGV_PKUERR
# define SEGV_PKUERR 4
#endif
static char *si_code_str(int si_code)
{
if (si_code == SEGV_MAPERR)
return "SEGV_MAPERR";
if (si_code == SEGV_ACCERR)
return "SEGV_ACCERR";
if (si_code == SEGV_BNDERR)
return "SEGV_BNDERR";
if (si_code == SEGV_PKUERR)
return "SEGV_PKUERR";
return "UNKNOWN";
}
int pkey_faults;
int last_si_pkey = -1;
void signal_handler(int signum, siginfo_t *si, void *vucontext)
{
ucontext_t *uctxt = vucontext;
int trapno;
unsigned long ip;
char *fpregs;
u32 *pkey_reg_ptr;
u64 siginfo_pkey;
u32 *si_pkey_ptr;
int pkey_reg_offset;
fpregset_t fpregset;
dprint_in_signal = 1;
dprintf1(">>>>===============SIGSEGV============================\n");
dprintf1("%s()::%d, pkey_reg: 0x%016llx shadow: %016llx\n",
__func__, __LINE__,
__read_pkey_reg(), shadow_pkey_reg);
trapno = uctxt->uc_mcontext.gregs[REG_TRAPNO];
ip = uctxt->uc_mcontext.gregs[REG_IP_IDX];
fpregset = uctxt->uc_mcontext.fpregs;
fpregs = (void *)fpregset;
dprintf2("%s() trapno: %d ip: 0x%016lx info->si_code: %s/%d\n",
__func__, trapno, ip, si_code_str(si->si_code),
si->si_code);
#ifdef __i386__
/*
* 32-bit has some extra padding so that userspace can tell whether
* the XSTATE header is present in addition to the "legacy" FPU
* state. We just assume that it is here.
*/
fpregs += 0x70;
#endif
pkey_reg_offset = pkey_reg_xstate_offset();
pkey_reg_ptr = (void *)(&fpregs[pkey_reg_offset]);
dprintf1("siginfo: %p\n", si);
dprintf1(" fpregs: %p\n", fpregs);
/*
* If we got a PKEY fault, we *HAVE* to have at least one bit set in
* here.
*/
dprintf1("pkey_reg_xstate_offset: %d\n", pkey_reg_xstate_offset());
if (DEBUG_LEVEL > 4)
dump_mem(pkey_reg_ptr - 128, 256);
pkey_assert(*pkey_reg_ptr);
if ((si->si_code == SEGV_MAPERR) ||
(si->si_code == SEGV_ACCERR) ||
(si->si_code == SEGV_BNDERR)) {
printf("non-PK si_code, exiting...\n");
exit(4);
}
si_pkey_ptr = (u32 *)(((u8 *)si) + si_pkey_offset);
dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
dump_mem((u8 *)si_pkey_ptr - 8, 24);
siginfo_pkey = *si_pkey_ptr;
pkey_assert(siginfo_pkey < NR_PKEYS);
last_si_pkey = siginfo_pkey;
dprintf1("signal pkey_reg from xsave: %08x\n", *pkey_reg_ptr);
/*
* need __read_pkey_reg() version so we do not do shadow_pkey_reg
* checking
*/
dprintf1("signal pkey_reg from pkey_reg: %016llx\n",
__read_pkey_reg());
dprintf1("pkey from siginfo: %016llx\n", siginfo_pkey);
*(u64 *)pkey_reg_ptr = 0x00000000;
dprintf1("WARNING: set PKEY_REG=0 to allow faulting instruction to continue\n");
pkey_faults++;
dprintf1("<<<<==================================================\n");
dprint_in_signal = 0;
}
int wait_all_children(void)
{
int status;
return waitpid(-1, &status, 0);
}
void sig_chld(int x)
{
dprint_in_signal = 1;
dprintf2("[%d] SIGCHLD: %d\n", getpid(), x);
dprint_in_signal = 0;
}
void setup_sigsegv_handler(void)
{
int r, rs;
struct sigaction newact;
struct sigaction oldact;
/* #PF is mapped to sigsegv */
int signum = SIGSEGV;
newact.sa_handler = 0;
newact.sa_sigaction = signal_handler;
/*sigset_t - signals to block while in the handler */
/* get the old signal mask. */
rs = sigprocmask(SIG_SETMASK, 0, &newact.sa_mask);
pkey_assert(rs == 0);
/* call sa_sigaction, not sa_handler*/
newact.sa_flags = SA_SIGINFO;
newact.sa_restorer = 0; /* void(*)(), obsolete */
r = sigaction(signum, &newact, &oldact);
r = sigaction(SIGALRM, &newact, &oldact);
pkey_assert(r == 0);
}
void setup_handlers(void)
{
signal(SIGCHLD, &sig_chld);
setup_sigsegv_handler();
}
pid_t fork_lazy_child(void)
{
pid_t forkret;
forkret = fork();
pkey_assert(forkret >= 0);
dprintf3("[%d] fork() ret: %d\n", getpid(), forkret);
if (!forkret) {
/* in the child */
while (1) {
dprintf1("child sleeping...\n");
sleep(30);
}
}
return forkret;
}
static u32 hw_pkey_get(int pkey, unsigned long flags)
{
u64 pkey_reg = __read_pkey_reg();
@ -452,6 +288,179 @@ void pkey_access_deny(int pkey)
pkey_disable_set(pkey, PKEY_DISABLE_ACCESS);
}
/* Failed address bound checks: */
#ifndef SEGV_BNDERR
# define SEGV_BNDERR 3
#endif
#ifndef SEGV_PKUERR
# define SEGV_PKUERR 4
#endif
static char *si_code_str(int si_code)
{
if (si_code == SEGV_MAPERR)
return "SEGV_MAPERR";
if (si_code == SEGV_ACCERR)
return "SEGV_ACCERR";
if (si_code == SEGV_BNDERR)
return "SEGV_BNDERR";
if (si_code == SEGV_PKUERR)
return "SEGV_PKUERR";
return "UNKNOWN";
}
int pkey_faults;
int last_si_pkey = -1;
void signal_handler(int signum, siginfo_t *si, void *vucontext)
{
ucontext_t *uctxt = vucontext;
int trapno;
unsigned long ip;
char *fpregs;
#if defined(__i386__) || defined(__x86_64__) /* arch */
u32 *pkey_reg_ptr;
int pkey_reg_offset;
#endif /* arch */
u64 siginfo_pkey;
u32 *si_pkey_ptr;
dprint_in_signal = 1;
dprintf1(">>>>===============SIGSEGV============================\n");
dprintf1("%s()::%d, pkey_reg: 0x%016llx shadow: %016llx\n",
__func__, __LINE__,
__read_pkey_reg(), shadow_pkey_reg);
trapno = uctxt->uc_mcontext.gregs[REG_TRAPNO];
ip = uctxt->uc_mcontext.gregs[REG_IP_IDX];
fpregs = (char *) uctxt->uc_mcontext.fpregs;
dprintf2("%s() trapno: %d ip: 0x%016lx info->si_code: %s/%d\n",
__func__, trapno, ip, si_code_str(si->si_code),
si->si_code);
#if defined(__i386__) || defined(__x86_64__) /* arch */
#ifdef __i386__
/*
* 32-bit has some extra padding so that userspace can tell whether
* the XSTATE header is present in addition to the "legacy" FPU
* state. We just assume that it is here.
*/
fpregs += 0x70;
#endif /* i386 */
pkey_reg_offset = pkey_reg_xstate_offset();
pkey_reg_ptr = (void *)(&fpregs[pkey_reg_offset]);
/*
* If we got a PKEY fault, we *HAVE* to have at least one bit set in
* here.
*/
dprintf1("pkey_reg_xstate_offset: %d\n", pkey_reg_xstate_offset());
if (DEBUG_LEVEL > 4)
dump_mem(pkey_reg_ptr - 128, 256);
pkey_assert(*pkey_reg_ptr);
#endif /* arch */
dprintf1("siginfo: %p\n", si);
dprintf1(" fpregs: %p\n", fpregs);
if ((si->si_code == SEGV_MAPERR) ||
(si->si_code == SEGV_ACCERR) ||
(si->si_code == SEGV_BNDERR)) {
printf("non-PK si_code, exiting...\n");
exit(4);
}
si_pkey_ptr = siginfo_get_pkey_ptr(si);
dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
dump_mem((u8 *)si_pkey_ptr - 8, 24);
siginfo_pkey = *si_pkey_ptr;
pkey_assert(siginfo_pkey < NR_PKEYS);
last_si_pkey = siginfo_pkey;
/*
* need __read_pkey_reg() version so we do not do shadow_pkey_reg
* checking
*/
dprintf1("signal pkey_reg from pkey_reg: %016llx\n",
__read_pkey_reg());
dprintf1("pkey from siginfo: %016llx\n", siginfo_pkey);
#if defined(__i386__) || defined(__x86_64__) /* arch */
dprintf1("signal pkey_reg from xsave: %08x\n", *pkey_reg_ptr);
*(u64 *)pkey_reg_ptr = 0x00000000;
dprintf1("WARNING: set PKEY_REG=0 to allow faulting instruction to continue\n");
#elif defined(__powerpc64__) /* arch */
/* restore access and let the faulting instruction continue */
pkey_access_allow(siginfo_pkey);
#endif /* arch */
pkey_faults++;
dprintf1("<<<<==================================================\n");
dprint_in_signal = 0;
}
int wait_all_children(void)
{
int status;
return waitpid(-1, &status, 0);
}
void sig_chld(int x)
{
dprint_in_signal = 1;
dprintf2("[%d] SIGCHLD: %d\n", getpid(), x);
dprint_in_signal = 0;
}
void setup_sigsegv_handler(void)
{
int r, rs;
struct sigaction newact;
struct sigaction oldact;
/* #PF is mapped to sigsegv */
int signum = SIGSEGV;
newact.sa_handler = 0;
newact.sa_sigaction = signal_handler;
/*sigset_t - signals to block while in the handler */
/* get the old signal mask. */
rs = sigprocmask(SIG_SETMASK, 0, &newact.sa_mask);
pkey_assert(rs == 0);
/* call sa_sigaction, not sa_handler*/
newact.sa_flags = SA_SIGINFO;
newact.sa_restorer = 0; /* void(*)(), obsolete */
r = sigaction(signum, &newact, &oldact);
r = sigaction(SIGALRM, &newact, &oldact);
pkey_assert(r == 0);
}
void setup_handlers(void)
{
signal(SIGCHLD, &sig_chld);
setup_sigsegv_handler();
}
pid_t fork_lazy_child(void)
{
pid_t forkret;
forkret = fork();
pkey_assert(forkret >= 0);
dprintf3("[%d] fork() ret: %d\n", getpid(), forkret);
if (!forkret) {
/* in the child */
while (1) {
dprintf1("child sleeping...\n");
sleep(30);
}
}
return forkret;
}
int sys_mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot,
unsigned long pkey)
{
@ -890,11 +899,15 @@ void expected_pkey_fault(int pkey)
if (pkey != UNKNOWN_PKEY)
pkey_assert(last_si_pkey == pkey);
#if defined(__i386__) || defined(__x86_64__) /* arch */
/*
* The signal handler shold have cleared out PKEY register to let the
* test program continue. We now have to restore it.
*/
if (__read_pkey_reg() != 0)
#else /* arch */
if (__read_pkey_reg() != shadow_pkey_reg)
#endif /* arch */
pkey_assert(0);
__write_pkey_reg(shadow_pkey_reg);