renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-25 13:43:55 +08:00
Code
ecec5ba681
linux-next/arch/um/sys-x86_64/signal.c
Jeff Dike 377fad3acb uml: kernel segfaults should dump proper registers 
If there's a segfault inside the kernel, we want a dump of the registers at
the point of the segfault, not the registers at the point of calling panic or
the last userspace registers.

sig_handler_common_skas now uses a static register set in the case of a
SIGSEGV to avoid messing up the process registers if the segfault turns out to
be non-fatal.

The architecture sigcontext-to-pt_regs copying code was repurposed to copy
data out of the SEGV stack frame.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:02 -07:00

347 lines
10 KiB
C
Raw Blame History

/*
* Copyright (C) 2003 PathScale, Inc.
* Licensed under the GPL
*/
#include "linux/stddef.h"
#include "linux/errno.h"
#include "linux/personality.h"
#include "linux/ptrace.h"
#include "asm/current.h"
#include "asm/uaccess.h"
#include "asm/sigcontext.h"
#include "asm/ptrace.h"
#include "asm/arch/ucontext.h"
#include "choose-mode.h"
#include "sysdep/ptrace.h"
#include "frame_kern.h"
#ifdef CONFIG_MODE_SKAS
#include "skas.h"
void copy_sc(union uml_pt_regs *regs, void *from)
{
struct sigcontext *sc = from;
#define GETREG(regs, regno, sc, regname) \
(regs)->skas.regs[(regno) / sizeof(unsigned long)] = (sc)->regname
GETREG(regs, R8, sc, r8);
GETREG(regs, R9, sc, r9);
GETREG(regs, R10, sc, r10);
GETREG(regs, R11, sc, r11);
GETREG(regs, R12, sc, r12);
GETREG(regs, R13, sc, r13);
GETREG(regs, R14, sc, r14);
GETREG(regs, R15, sc, r15);
GETREG(regs, RDI, sc, rdi);
GETREG(regs, RSI, sc, rsi);
GETREG(regs, RBP, sc, rbp);
GETREG(regs, RBX, sc, rbx);
GETREG(regs, RDX, sc, rdx);
GETREG(regs, RAX, sc, rax);
GETREG(regs, RCX, sc, rcx);
GETREG(regs, RSP, sc, rsp);
GETREG(regs, RIP, sc, rip);
GETREG(regs, EFLAGS, sc, eflags);
GETREG(regs, CS, sc, cs);
#undef GETREG
}
static int copy_sc_from_user_skas(struct pt_regs *regs,
struct sigcontext __user *from)
{
int err = 0;
#define GETREG(regs, regno, sc, regname) \
__get_user((regs)->regs.skas.regs[(regno) / sizeof(unsigned long)], \
&(sc)->regname)
err |= GETREG(regs, R8, from, r8);
err |= GETREG(regs, R9, from, r9);
err |= GETREG(regs, R10, from, r10);
err |= GETREG(regs, R11, from, r11);
err |= GETREG(regs, R12, from, r12);
err |= GETREG(regs, R13, from, r13);
err |= GETREG(regs, R14, from, r14);
err |= GETREG(regs, R15, from, r15);
err |= GETREG(regs, RDI, from, rdi);
err |= GETREG(regs, RSI, from, rsi);
err |= GETREG(regs, RBP, from, rbp);
err |= GETREG(regs, RBX, from, rbx);
err |= GETREG(regs, RDX, from, rdx);
err |= GETREG(regs, RAX, from, rax);
err |= GETREG(regs, RCX, from, rcx);
err |= GETREG(regs, RSP, from, rsp);
err |= GETREG(regs, RIP, from, rip);
err |= GETREG(regs, EFLAGS, from, eflags);
err |= GETREG(regs, CS, from, cs);
#undef GETREG
return err;
}
int copy_sc_to_user_skas(struct sigcontext __user *to,
struct _fpstate __user *to_fp,
struct pt_regs *regs, unsigned long mask,
unsigned long sp)
{
struct faultinfo * fi = &current->thread.arch.faultinfo;
int err = 0;
err |= __put_user(0, &to->gs);
err |= __put_user(0, &to->fs);
#define PUTREG(regs, regno, sc, regname) \
__put_user((regs)->regs.skas.regs[(regno) / sizeof(unsigned long)], \
&(sc)->regname)
err |= PUTREG(regs, RDI, to, rdi);
err |= PUTREG(regs, RSI, to, rsi);
err |= PUTREG(regs, RBP, to, rbp);
/* Must use orignal RSP, which is passed in, rather than what's in
* the pt_regs, because that's already been updated to point at the
* signal frame.
*/
err |= __put_user(sp, &to->rsp);
err |= PUTREG(regs, RBX, to, rbx);
err |= PUTREG(regs, RDX, to, rdx);
err |= PUTREG(regs, RCX, to, rcx);
err |= PUTREG(regs, RAX, to, rax);
err |= PUTREG(regs, R8, to, r8);
err |= PUTREG(regs, R9, to, r9);
err |= PUTREG(regs, R10, to, r10);
err |= PUTREG(regs, R11, to, r11);
err |= PUTREG(regs, R12, to, r12);
err |= PUTREG(regs, R13, to, r13);
err |= PUTREG(regs, R14, to, r14);
err |= PUTREG(regs, R15, to, r15);
err |= PUTREG(regs, CS, to, cs); /* XXX x86_64 doesn't do this */
err |= __put_user(fi->cr2, &to->cr2);
err |= __put_user(fi->error_code, &to->err);
err |= __put_user(fi->trap_no, &to->trapno);
err |= PUTREG(regs, RIP, to, rip);
err |= PUTREG(regs, EFLAGS, to, eflags);
#undef PUTREG
err |= __put_user(mask, &to->oldmask);
return(err);
}
#endif
#ifdef CONFIG_MODE_TT
int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
int fpsize)
{
struct _fpstate *to_fp;
struct _fpstate __user *from_fp;
unsigned long sigs;
int err;
to_fp = to->fpstate;
sigs = to->oldmask;
err = copy_from_user(to, from, sizeof(*to));
from_fp = to->fpstate;
to->fpstate = to_fp;
to->oldmask = sigs;
if(to_fp != NULL)
err |= copy_from_user(to_fp, from_fp, fpsize);
return(err);
}
int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
struct sigcontext *from, int fpsize, unsigned long sp)
{
struct _fpstate __user *to_fp;
struct _fpstate *from_fp;
int err;
to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
from_fp = from->fpstate;
err = copy_to_user(to, from, sizeof(*to));
/* The SP in the sigcontext is the updated one for the signal
* delivery. The sp passed in is the original, and this needs
* to be restored, so we stick it in separately.
*/
err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
if(from_fp != NULL){
err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
err |= copy_to_user(to_fp, from_fp, fpsize);
}
return err;
}
#endif
static int copy_sc_from_user(struct pt_regs *to, void __user *from)
{
int ret;
ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
sizeof(struct _fpstate)),
copy_sc_from_user_skas(to, from));
return(ret);
}
static int copy_sc_to_user(struct sigcontext __user *to,
struct _fpstate __user *fp,
struct pt_regs *from, unsigned long mask,
unsigned long sp)
{
return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
sizeof(*fp), sp),
copy_sc_to_user_skas(to, fp, from, mask, sp)));
}
struct rt_sigframe
{
char __user *pretcode;
struct ucontext uc;
struct siginfo info;
};
#define round_down(m, n) (((m) / (n)) * (n))
int setup_signal_stack_si(unsigned long stack_top, int sig,
struct k_sigaction *ka, struct pt_regs * regs,
siginfo_t *info, sigset_t *set)
{
struct rt_sigframe __user *frame;
struct _fpstate __user *fp = NULL;
unsigned long save_sp = PT_REGS_RSP(regs);
int err = 0;
struct task_struct *me = current;
frame = (struct rt_sigframe __user *)
round_down(stack_top - sizeof(struct rt_sigframe), 16);
/* Subtract 128 for a red zone and 8 for proper alignment */
frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
goto out;
#if 0 /* XXX */
if (save_i387(fp) < 0)
err |= -1;
#endif
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto out;
if (ka->sa.sa_flags & SA_SIGINFO) {
err |= copy_siginfo_to_user(&frame->info, info);
if (err)
goto out;
}
/* Update SP now because the page fault handler refuses to extend
* the stack if the faulting address is too far below the current
* SP, which frame now certainly is. If there's an error, the original
* value is restored on the way out.
* When writing the sigcontext to the stack, we have to write the
* original value, so that's passed to copy_sc_to_user, which does
* the right thing with it.
*/
PT_REGS_RSP(regs) = (unsigned long) frame;
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(save_sp),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= copy_sc_to_user(&frame->uc.uc_mcontext, fp, regs, set->sig[0],
save_sp);
err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
if (sizeof(*set) == 16) {
__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
}
else
err |= __copy_to_user(&frame->uc.uc_sigmask, set,
sizeof(*set));
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
/* x86-64 should always use SA_RESTORER. */
if (ka->sa.sa_flags & SA_RESTORER)
err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
else
/* could use a vstub here */
goto restore_sp;
if (err)
goto restore_sp;
/* Set up registers for signal handler */
{
struct exec_domain *ed = current_thread_info()->exec_domain;
if (unlikely(ed && ed->signal_invmap && sig < 32))
sig = ed->signal_invmap[sig];
}
PT_REGS_RDI(regs) = sig;
/* In case the signal handler was declared without prototypes */
PT_REGS_RAX(regs) = 0;
/* This also works for non SA_SIGINFO handlers because they expect the
next argument after the signal number on the stack. */
PT_REGS_RSI(regs) = (unsigned long) &frame->info;
PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
out:
return err;
restore_sp:
PT_REGS_RSP(regs) = save_sp;
return err;
}
long sys_rt_sigreturn(struct pt_regs *regs)
{
unsigned long sp = PT_REGS_SP(&current->thread.regs);
struct rt_sigframe __user *frame =
(struct rt_sigframe __user *)(sp - 8);
struct ucontext __user *uc = &frame->uc;
sigset_t set;
if(copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
goto segfault;
sigdelsetmask(&set, ~_BLOCKABLE);
spin_lock_irq(&current->sighand->siglock);
current->blocked = set;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
goto segfault;
/* Avoid ERESTART handling */
PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
return(PT_REGS_SYSCALL_RET(&current->thread.regs));
segfault:
force_sig(SIGSEGV, current);
return 0;
}
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
View Git Blame Copy Permalink