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linux/arch/sparc/kernel/signal32.c
Marco Elver 78ed93d72d signal: Deliver SIGTRAP on perf event asynchronously if blocked 
With SIGTRAP on perf events, we have encountered termination of
processes due to user space attempting to block delivery of SIGTRAP.
Consider this case:

    <set up SIGTRAP on a perf event>
    ...
    sigset_t s;
    sigemptyset(&s);
    sigaddset(&s, SIGTRAP | <and others>);
    sigprocmask(SIG_BLOCK, &s, ...);
    ...
    <perf event triggers>

When the perf event triggers, while SIGTRAP is blocked, force_sig_perf()
will force the signal, but revert back to the default handler, thus
terminating the task.

This makes sense for error conditions, but not so much for explicitly
requested monitoring. However, the expectation is still that signals
generated by perf events are synchronous, which will no longer be the
case if the signal is blocked and delivered later.

To give user space the ability to clearly distinguish synchronous from
asynchronous signals, introduce siginfo_t::si_perf_flags and
TRAP_PERF_FLAG_ASYNC (opted for flags in case more binary information is
required in future).

The resolution to the problem is then to (a) no longer force the signal
(avoiding the terminations), but (b) tell user space via si_perf_flags
if the signal was synchronous or not, so that such signals can be
handled differently (e.g. let user space decide to ignore or consider
the data imprecise).

The alternative of making the kernel ignore SIGTRAP on perf events if
the signal is blocked may work for some usecases, but likely causes
issues in others that then have to revert back to interception of
sigprocmask() (which we want to avoid). [ A concrete example: when using
breakpoint perf events to track data-flow, in a region of code where
signals are blocked, data-flow can no longer be tracked accurately.
When a relevant asynchronous signal is received after unblocking the
signal, the data-flow tracking logic needs to know its state is
imprecise. ]

Fixes: 97ba62b278 ("perf: Add support for SIGTRAP on perf events")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/r/20220404111204.935357-1-elver@google.com
2022-04-22 12:14:05 +02:00

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// SPDX-License-Identifier: GPL-2.0
/* arch/sparc64/kernel/signal32.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
* Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
* Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/compat.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <asm/ptrace.h>
#include <asm/psrcompat.h>
#include <asm/fpumacro.h>
#include <asm/visasm.h>
#include <asm/compat_signal.h>
#include <asm/switch_to.h>
#include "sigutil.h"
#include "kernel.h"
/* This magic should be in g_upper[0] for all upper parts
* to be valid.
*/
#define SIGINFO_EXTRA_V8PLUS_MAGIC 0x130e269
typedef struct {
unsigned int g_upper[8];
unsigned int o_upper[8];
unsigned int asi;
} siginfo_extra_v8plus_t;
struct signal_frame32 {
struct sparc_stackf32 ss;
__siginfo32_t info;
/* __siginfo_fpu_t * */ u32 fpu_save;
unsigned int insns[2];
unsigned int extramask[_COMPAT_NSIG_WORDS - 1];
unsigned int extra_size; /* Should be sizeof(siginfo_extra_v8plus_t) */
/* Only valid if (info.si_regs.psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS */
siginfo_extra_v8plus_t v8plus;
/* __siginfo_rwin_t * */u32 rwin_save;
} __attribute__((aligned(8)));
struct rt_signal_frame32 {
struct sparc_stackf32 ss;
compat_siginfo_t info;
struct pt_regs32 regs;
compat_sigset_t mask;
/* __siginfo_fpu_t * */ u32 fpu_save;
unsigned int insns[2];
compat_stack_t stack;
unsigned int extra_size; /* Should be sizeof(siginfo_extra_v8plus_t) */
/* Only valid if (regs.psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS */
siginfo_extra_v8plus_t v8plus;
/* __siginfo_rwin_t * */u32 rwin_save;
} __attribute__((aligned(8)));
/* Checks if the fp is valid. We always build signal frames which are
* 16-byte aligned, therefore we can always enforce that the restore
* frame has that property as well.
*/
static bool invalid_frame_pointer(void __user *fp, int fplen)
{
if ((((unsigned long) fp) & 15) ||
((unsigned long)fp) > 0x100000000ULL - fplen)
return true;
return false;
}
void do_sigreturn32(struct pt_regs *regs)
{
struct signal_frame32 __user *sf;
compat_uptr_t fpu_save;
compat_uptr_t rwin_save;
unsigned int psr, ufp;
unsigned int pc, npc;
sigset_t set;
compat_sigset_t seta;
int err, i;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
synchronize_user_stack();
regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
sf = (struct signal_frame32 __user *) regs->u_regs[UREG_FP];
/* 1. Make sure we are not getting garbage from the user */
if (invalid_frame_pointer(sf, sizeof(*sf)))
goto segv;
if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP]))
goto segv;
if (ufp & 0x7)
goto segv;
if (__get_user(pc, &sf->info.si_regs.pc) ||
__get_user(npc, &sf->info.si_regs.npc))
goto segv;
if ((pc | npc) & 3)
goto segv;
if (test_thread_flag(TIF_32BIT)) {
pc &= 0xffffffff;
npc &= 0xffffffff;
}
regs->tpc = pc;
regs->tnpc = npc;
/* 2. Restore the state */
err = __get_user(regs->y, &sf->info.si_regs.y);
err |= __get_user(psr, &sf->info.si_regs.psr);
for (i = UREG_G1; i <= UREG_I7; i++)
err |= __get_user(regs->u_regs[i], &sf->info.si_regs.u_regs[i]);
if ((psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS) {
err |= __get_user(i, &sf->v8plus.g_upper[0]);
if (i == SIGINFO_EXTRA_V8PLUS_MAGIC) {
unsigned long asi;
for (i = UREG_G1; i <= UREG_I7; i++)
err |= __get_user(((u32 *)regs->u_regs)[2*i], &sf->v8plus.g_upper[i]);
err |= __get_user(asi, &sf->v8plus.asi);
regs->tstate &= ~TSTATE_ASI;
regs->tstate |= ((asi & 0xffUL) << 24UL);
}
}
/* User can only change condition codes in %tstate. */
regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
regs->tstate |= psr_to_tstate_icc(psr);
/* Prevent syscall restart. */
pt_regs_clear_syscall(regs);
err |= __get_user(fpu_save, &sf->fpu_save);
if (!err && fpu_save)
err |= restore_fpu_state(regs, compat_ptr(fpu_save));
err |= __get_user(rwin_save, &sf->rwin_save);
if (!err && rwin_save) {
if (restore_rwin_state(compat_ptr(rwin_save)))
goto segv;
}
err |= __get_user(seta.sig[0], &sf->info.si_mask);
err |= copy_from_user(&seta.sig[1], &sf->extramask,
(_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));
if (err)
goto segv;
set.sig[0] = seta.sig[0] + (((long)seta.sig[1]) << 32);
set_current_blocked(&set);
return;
segv:
force_sig(SIGSEGV);
}
asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
{
struct rt_signal_frame32 __user *sf;
unsigned int psr, pc, npc, ufp;
compat_uptr_t fpu_save;
compat_uptr_t rwin_save;
sigset_t set;
int err, i;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
synchronize_user_stack();
regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
sf = (struct rt_signal_frame32 __user *) regs->u_regs[UREG_FP];
/* 1. Make sure we are not getting garbage from the user */
if (invalid_frame_pointer(sf, sizeof(*sf)))
goto segv;
if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
goto segv;
if (ufp & 0x7)
goto segv;
if (__get_user(pc, &sf->regs.pc) ||
__get_user(npc, &sf->regs.npc))
goto segv;
if ((pc | npc) & 3)
goto segv;
if (test_thread_flag(TIF_32BIT)) {
pc &= 0xffffffff;
npc &= 0xffffffff;
}
regs->tpc = pc;
regs->tnpc = npc;
/* 2. Restore the state */
err = __get_user(regs->y, &sf->regs.y);
err |= __get_user(psr, &sf->regs.psr);
for (i = UREG_G1; i <= UREG_I7; i++)
err |= __get_user(regs->u_regs[i], &sf->regs.u_regs[i]);
if ((psr & (PSR_VERS|PSR_IMPL)) == PSR_V8PLUS) {
err |= __get_user(i, &sf->v8plus.g_upper[0]);
if (i == SIGINFO_EXTRA_V8PLUS_MAGIC) {
unsigned long asi;
for (i = UREG_G1; i <= UREG_I7; i++)
err |= __get_user(((u32 *)regs->u_regs)[2*i], &sf->v8plus.g_upper[i]);
err |= __get_user(asi, &sf->v8plus.asi);
regs->tstate &= ~TSTATE_ASI;
regs->tstate |= ((asi & 0xffUL) << 24UL);
}
}
/* User can only change condition codes in %tstate. */
regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
regs->tstate |= psr_to_tstate_icc(psr);
/* Prevent syscall restart. */
pt_regs_clear_syscall(regs);
err |= __get_user(fpu_save, &sf->fpu_save);
if (!err && fpu_save)
err |= restore_fpu_state(regs, compat_ptr(fpu_save));
err |= get_compat_sigset(&set, &sf->mask);
err |= compat_restore_altstack(&sf->stack);
if (err)
goto segv;
err |= __get_user(rwin_save, &sf->rwin_save);
if (!err && rwin_save) {
if (restore_rwin_state(compat_ptr(rwin_save)))
goto segv;
}
set_current_blocked(&set);
return;
segv:
force_sig(SIGSEGV);
}
static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
{
unsigned long sp;
regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
sp = regs->u_regs[UREG_FP];
/*
* If we are on the alternate signal stack and would overflow it, don't.
* Return an always-bogus address instead so we will die with SIGSEGV.
*/
if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
return (void __user *) -1L;
/* This is the X/Open sanctioned signal stack switching. */
sp = sigsp(sp, ksig) - framesize;
/* Always align the stack frame. This handles two cases. First,
* sigaltstack need not be mindful of platform specific stack
* alignment. Second, if we took this signal because the stack
* is not aligned properly, we'd like to take the signal cleanly
* and report that.
*/
sp &= ~15UL;
return (void __user *) sp;
}
/* The I-cache flush instruction only works in the primary ASI, which
* right now is the nucleus, aka. kernel space.
*
* Therefore we have to kick the instructions out using the kernel
* side linear mapping of the physical address backing the user
* instructions.
*/
static void flush_signal_insns(unsigned long address)
{
unsigned long pstate, paddr;
pte_t *ptep, pte;
pgd_t *pgdp;
p4d_t *p4dp;
pud_t *pudp;
pmd_t *pmdp;
/* Commit all stores of the instructions we are about to flush. */
wmb();
/* Disable cross-call reception. In this way even a very wide
* munmap() on another cpu can't tear down the page table
* hierarchy from underneath us, since that can't complete
* until the IPI tlb flush returns.
*/
__asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
__asm__ __volatile__("wrpr %0, %1, %%pstate"
: : "r" (pstate), "i" (PSTATE_IE));
pgdp = pgd_offset(current->mm, address);
if (pgd_none(*pgdp))
goto out_irqs_on;
p4dp = p4d_offset(pgdp, address);
if (p4d_none(*p4dp))
goto out_irqs_on;
pudp = pud_offset(p4dp, address);
if (pud_none(*pudp))
goto out_irqs_on;
pmdp = pmd_offset(pudp, address);
if (pmd_none(*pmdp))
goto out_irqs_on;
ptep = pte_offset_map(pmdp, address);
pte = *ptep;
if (!pte_present(pte))
goto out_unmap;
paddr = (unsigned long) page_address(pte_page(pte));
__asm__ __volatile__("flush %0 + %1"
: /* no outputs */
: "r" (paddr),
"r" (address & (PAGE_SIZE - 1))
: "memory");
out_unmap:
pte_unmap(ptep);
out_irqs_on:
__asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate));
}
static int setup_frame32(struct ksignal *ksig, struct pt_regs *regs,
sigset_t *oldset)
{
struct signal_frame32 __user *sf;
int i, err, wsaved;
void __user *tail;
int sigframe_size;
u32 psr;
compat_sigset_t seta;
/* 1. Make sure everything is clean */
synchronize_user_stack();
save_and_clear_fpu();
wsaved = get_thread_wsaved();
sigframe_size = sizeof(*sf);
if (current_thread_info()->fpsaved[0] & FPRS_FEF)
sigframe_size += sizeof(__siginfo_fpu_t);
if (wsaved)
sigframe_size += sizeof(__siginfo_rwin_t);
sf = (struct signal_frame32 __user *)
get_sigframe(ksig, regs, sigframe_size);
if (invalid_frame_pointer(sf, sigframe_size)) {
if (show_unhandled_signals)
pr_info("%s[%d] bad frame in setup_frame32: %08lx TPC %08lx O7 %08lx\n",
current->comm, current->pid, (unsigned long)sf,
regs->tpc, regs->u_regs[UREG_I7]);
force_sigsegv(ksig->sig);
return -EINVAL;
}
tail = (sf + 1);
/* 2. Save the current process state */
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
err = put_user(regs->tpc, &sf->info.si_regs.pc);
err |= __put_user(regs->tnpc, &sf->info.si_regs.npc);
err |= __put_user(regs->y, &sf->info.si_regs.y);
psr = tstate_to_psr(regs->tstate);
if (current_thread_info()->fpsaved[0] & FPRS_FEF)
psr |= PSR_EF;
err |= __put_user(psr, &sf->info.si_regs.psr);
for (i = 0; i < 16; i++)
err |= __put_user(regs->u_regs[i], &sf->info.si_regs.u_regs[i]);
err |= __put_user(sizeof(siginfo_extra_v8plus_t), &sf->extra_size);
err |= __put_user(SIGINFO_EXTRA_V8PLUS_MAGIC, &sf->v8plus.g_upper[0]);
for (i = 1; i < 16; i++)
err |= __put_user(((u32 *)regs->u_regs)[2*i],
&sf->v8plus.g_upper[i]);
err |= __put_user((regs->tstate & TSTATE_ASI) >> 24UL,
&sf->v8plus.asi);
if (psr & PSR_EF) {
__siginfo_fpu_t __user *fp = tail;
tail += sizeof(*fp);
err |= save_fpu_state(regs, fp);
err |= __put_user((u64)fp, &sf->fpu_save);
} else {
err |= __put_user(0, &sf->fpu_save);
}
if (wsaved) {
__siginfo_rwin_t __user *rwp = tail;
tail += sizeof(*rwp);
err |= save_rwin_state(wsaved, rwp);
err |= __put_user((u64)rwp, &sf->rwin_save);
set_thread_wsaved(0);
} else {
err |= __put_user(0, &sf->rwin_save);
}
/* If these change we need to know - assignments to seta relies on these sizes */
BUILD_BUG_ON(_NSIG_WORDS != 1);
BUILD_BUG_ON(_COMPAT_NSIG_WORDS != 2);
seta.sig[1] = (oldset->sig[0] >> 32);
seta.sig[0] = oldset->sig[0];
err |= __put_user(seta.sig[0], &sf->info.si_mask);
err |= __copy_to_user(sf->extramask, &seta.sig[1],
(_COMPAT_NSIG_WORDS - 1) * sizeof(unsigned int));
if (!wsaved) {
err |= raw_copy_in_user((u32 __user *)sf,
(u32 __user *)(regs->u_regs[UREG_FP]),
sizeof(struct reg_window32));
} else {
struct reg_window *rp;
rp = &current_thread_info()->reg_window[wsaved - 1];
for (i = 0; i < 8; i++)
err |= __put_user(rp->locals[i], &sf->ss.locals[i]);
for (i = 0; i < 6; i++)
err |= __put_user(rp->ins[i], &sf->ss.ins[i]);
err |= __put_user(rp->ins[6], &sf->ss.fp);
err |= __put_user(rp->ins[7], &sf->ss.callers_pc);
}
if (err)
return err;
/* 3. signal handler back-trampoline and parameters */
regs->u_regs[UREG_FP] = (unsigned long) sf;
regs->u_regs[UREG_I0] = ksig->sig;
regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
/* 4. signal handler */
regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
regs->tnpc = (regs->tpc + 4);
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
/* 5. return to kernel instructions */
if (ksig->ka.ka_restorer) {
regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
} else {
unsigned long address = ((unsigned long)&(sf->insns[0]));
regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
err = __put_user(0x821020d8, &sf->insns[0]); /*mov __NR_sigreturn, %g1*/
err |= __put_user(0x91d02010, &sf->insns[1]); /*t 0x10*/
if (err)
return err;
flush_signal_insns(address);
}
return 0;
}
static int setup_rt_frame32(struct ksignal *ksig, struct pt_regs *regs,
sigset_t *oldset)
{
struct rt_signal_frame32 __user *sf;
int i, err, wsaved;
void __user *tail;
int sigframe_size;
u32 psr;
/* 1. Make sure everything is clean */
synchronize_user_stack();
save_and_clear_fpu();
wsaved = get_thread_wsaved();
sigframe_size = sizeof(*sf);
if (current_thread_info()->fpsaved[0] & FPRS_FEF)
sigframe_size += sizeof(__siginfo_fpu_t);
if (wsaved)
sigframe_size += sizeof(__siginfo_rwin_t);
sf = (struct rt_signal_frame32 __user *)
get_sigframe(ksig, regs, sigframe_size);
if (invalid_frame_pointer(sf, sigframe_size)) {
if (show_unhandled_signals)
pr_info("%s[%d] bad frame in setup_rt_frame32: %08lx TPC %08lx O7 %08lx\n",
current->comm, current->pid, (unsigned long)sf,
regs->tpc, regs->u_regs[UREG_I7]);
force_sigsegv(ksig->sig);
return -EINVAL;
}
tail = (sf + 1);
/* 2. Save the current process state */
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
err = put_user(regs->tpc, &sf->regs.pc);
err |= __put_user(regs->tnpc, &sf->regs.npc);
err |= __put_user(regs->y, &sf->regs.y);
psr = tstate_to_psr(regs->tstate);
if (current_thread_info()->fpsaved[0] & FPRS_FEF)
psr |= PSR_EF;
err |= __put_user(psr, &sf->regs.psr);
for (i = 0; i < 16; i++)
err |= __put_user(regs->u_regs[i], &sf->regs.u_regs[i]);
err |= __put_user(sizeof(siginfo_extra_v8plus_t), &sf->extra_size);
err |= __put_user(SIGINFO_EXTRA_V8PLUS_MAGIC, &sf->v8plus.g_upper[0]);
for (i = 1; i < 16; i++)
err |= __put_user(((u32 *)regs->u_regs)[2*i],
&sf->v8plus.g_upper[i]);
err |= __put_user((regs->tstate & TSTATE_ASI) >> 24UL,
&sf->v8plus.asi);
if (psr & PSR_EF) {
__siginfo_fpu_t __user *fp = tail;
tail += sizeof(*fp);
err |= save_fpu_state(regs, fp);
err |= __put_user((u64)fp, &sf->fpu_save);
} else {
err |= __put_user(0, &sf->fpu_save);
}
if (wsaved) {
__siginfo_rwin_t __user *rwp = tail;
tail += sizeof(*rwp);
err |= save_rwin_state(wsaved, rwp);
err |= __put_user((u64)rwp, &sf->rwin_save);
set_thread_wsaved(0);
} else {
err |= __put_user(0, &sf->rwin_save);
}
/* Update the siginfo structure. */
err |= copy_siginfo_to_user32(&sf->info, &ksig->info);
/* Setup sigaltstack */
err |= __compat_save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
err |= put_compat_sigset(&sf->mask, oldset, sizeof(compat_sigset_t));
if (!wsaved) {
err |= raw_copy_in_user((u32 __user *)sf,
(u32 __user *)(regs->u_regs[UREG_FP]),
sizeof(struct reg_window32));
} else {
struct reg_window *rp;
rp = &current_thread_info()->reg_window[wsaved - 1];
for (i = 0; i < 8; i++)
err |= __put_user(rp->locals[i], &sf->ss.locals[i]);
for (i = 0; i < 6; i++)
err |= __put_user(rp->ins[i], &sf->ss.ins[i]);
err |= __put_user(rp->ins[6], &sf->ss.fp);
err |= __put_user(rp->ins[7], &sf->ss.callers_pc);
}
if (err)
return err;
/* 3. signal handler back-trampoline and parameters */
regs->u_regs[UREG_FP] = (unsigned long) sf;
regs->u_regs[UREG_I0] = ksig->sig;
regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
/* 4. signal handler */
regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
regs->tnpc = (regs->tpc + 4);
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
/* 5. return to kernel instructions */
if (ksig->ka.ka_restorer)
regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
else {
unsigned long address = ((unsigned long)&(sf->insns[0]));
regs->u_regs[UREG_I7] = (unsigned long) (&(sf->insns[0]) - 2);
/* mov __NR_rt_sigreturn, %g1 */
err |= __put_user(0x82102065, &sf->insns[0]);
/* t 0x10 */
err |= __put_user(0x91d02010, &sf->insns[1]);
if (err)
return err;
flush_signal_insns(address);
}
return 0;
}
static inline void handle_signal32(struct ksignal *ksig,
struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int err;
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
err = setup_rt_frame32(ksig, regs, oldset);
else
err = setup_frame32(ksig, regs, oldset);
signal_setup_done(err, ksig, 0);
}
static inline void syscall_restart32(unsigned long orig_i0, struct pt_regs *regs,
struct sigaction *sa)
{
switch (regs->u_regs[UREG_I0]) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
no_system_call_restart:
regs->u_regs[UREG_I0] = EINTR;
regs->tstate |= TSTATE_ICARRY;
break;
case ERESTARTSYS:
if (!(sa->sa_flags & SA_RESTART))
goto no_system_call_restart;
fallthrough;
case ERESTARTNOINTR:
regs->u_regs[UREG_I0] = orig_i0;
regs->tpc -= 4;
regs->tnpc -= 4;
}
}
/* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*/
void do_signal32(struct pt_regs * regs)
{
struct ksignal ksig;
unsigned long orig_i0 = 0;
int restart_syscall = 0;
bool has_handler = get_signal(&ksig);
if (pt_regs_is_syscall(regs) &&
(regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
restart_syscall = 1;
orig_i0 = regs->u_regs[UREG_G6];
}
if (has_handler) {
if (restart_syscall)
syscall_restart32(orig_i0, regs, &ksig.ka.sa);
handle_signal32(&ksig, regs);
} else {
if (restart_syscall) {
switch (regs->u_regs[UREG_I0]) {
case ERESTARTNOHAND:
case ERESTARTSYS:
case ERESTARTNOINTR:
/* replay the system call when we are done */
regs->u_regs[UREG_I0] = orig_i0;
regs->tpc -= 4;
regs->tnpc -= 4;
pt_regs_clear_syscall(regs);
fallthrough;
case ERESTART_RESTARTBLOCK:
regs->u_regs[UREG_G1] = __NR_restart_syscall;
regs->tpc -= 4;
regs->tnpc -= 4;
pt_regs_clear_syscall(regs);
}
}
restore_saved_sigmask();
}
}
struct sigstack32 {
u32 the_stack;
int cur_status;
};
asmlinkage int do_sys32_sigstack(u32 u_ssptr, u32 u_ossptr, unsigned long sp)
{
struct sigstack32 __user *ssptr =
(struct sigstack32 __user *)((unsigned long)(u_ssptr));
struct sigstack32 __user *ossptr =
(struct sigstack32 __user *)((unsigned long)(u_ossptr));
int ret = -EFAULT;
/* First see if old state is wanted. */
if (ossptr) {
if (put_user(current->sas_ss_sp + current->sas_ss_size,
&ossptr->the_stack) ||
__put_user(on_sig_stack(sp), &ossptr->cur_status))
goto out;
}
/* Now see if we want to update the new state. */
if (ssptr) {
u32 ss_sp;
if (get_user(ss_sp, &ssptr->the_stack))
goto out;
/* If the current stack was set with sigaltstack, don't
* swap stacks while we are on it.
*/
ret = -EPERM;
if (current->sas_ss_sp && on_sig_stack(sp))
goto out;
/* Since we don't know the extent of the stack, and we don't
* track onstack-ness, but rather calculate it, we must
* presume a size. Ho hum this interface is lossy.
*/
current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
current->sas_ss_size = SIGSTKSZ;
}
ret = 0;
out:
return ret;
}
/*
* Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
* changes likely come with new fields that should be added below.
*/
static_assert(NSIGILL == 11);
static_assert(NSIGFPE == 15);
static_assert(NSIGSEGV == 9);
static_assert(NSIGBUS == 5);
static_assert(NSIGTRAP == 6);
static_assert(NSIGCHLD == 6);
static_assert(NSIGSYS == 2);
static_assert(sizeof(compat_siginfo_t) == 128);
static_assert(__alignof__(compat_siginfo_t) == 4);
static_assert(offsetof(compat_siginfo_t, si_signo) == 0x00);
static_assert(offsetof(compat_siginfo_t, si_errno) == 0x04);
static_assert(offsetof(compat_siginfo_t, si_code) == 0x08);
static_assert(offsetof(compat_siginfo_t, si_pid) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_uid) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_tid) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_overrun) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_status) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_utime) == 0x18);
static_assert(offsetof(compat_siginfo_t, si_stime) == 0x1c);
static_assert(offsetof(compat_siginfo_t, si_value) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_int) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_ptr) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_addr) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_trapno) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_addr_lsb) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_lower) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_upper) == 0x18);
static_assert(offsetof(compat_siginfo_t, si_pkey) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_perf_data) == 0x10);
static_assert(offsetof(compat_siginfo_t, si_perf_type) == 0x14);
static_assert(offsetof(compat_siginfo_t, si_perf_flags) == 0x18);
static_assert(offsetof(compat_siginfo_t, si_band) == 0x0c);
static_assert(offsetof(compat_siginfo_t, si_fd) == 0x10);
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