377fad3acb
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>
347 lines
10 KiB
C
347 lines
10 KiB
C
/*
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* Copyright (C) 2003 PathScale, Inc.
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* Licensed under the GPL
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*/
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#include "linux/stddef.h"
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#include "linux/errno.h"
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#include "linux/personality.h"
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#include "linux/ptrace.h"
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#include "asm/current.h"
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#include "asm/uaccess.h"
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#include "asm/sigcontext.h"
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#include "asm/ptrace.h"
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#include "asm/arch/ucontext.h"
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#include "choose-mode.h"
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#include "sysdep/ptrace.h"
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#include "frame_kern.h"
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#ifdef CONFIG_MODE_SKAS
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#include "skas.h"
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void copy_sc(union uml_pt_regs *regs, void *from)
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{
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struct sigcontext *sc = from;
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#define GETREG(regs, regno, sc, regname) \
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(regs)->skas.regs[(regno) / sizeof(unsigned long)] = (sc)->regname
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GETREG(regs, R8, sc, r8);
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GETREG(regs, R9, sc, r9);
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GETREG(regs, R10, sc, r10);
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GETREG(regs, R11, sc, r11);
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GETREG(regs, R12, sc, r12);
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GETREG(regs, R13, sc, r13);
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GETREG(regs, R14, sc, r14);
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GETREG(regs, R15, sc, r15);
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GETREG(regs, RDI, sc, rdi);
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GETREG(regs, RSI, sc, rsi);
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GETREG(regs, RBP, sc, rbp);
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GETREG(regs, RBX, sc, rbx);
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GETREG(regs, RDX, sc, rdx);
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GETREG(regs, RAX, sc, rax);
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GETREG(regs, RCX, sc, rcx);
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GETREG(regs, RSP, sc, rsp);
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GETREG(regs, RIP, sc, rip);
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GETREG(regs, EFLAGS, sc, eflags);
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GETREG(regs, CS, sc, cs);
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#undef GETREG
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}
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static int copy_sc_from_user_skas(struct pt_regs *regs,
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struct sigcontext __user *from)
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{
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int err = 0;
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#define GETREG(regs, regno, sc, regname) \
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__get_user((regs)->regs.skas.regs[(regno) / sizeof(unsigned long)], \
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&(sc)->regname)
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err |= GETREG(regs, R8, from, r8);
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err |= GETREG(regs, R9, from, r9);
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err |= GETREG(regs, R10, from, r10);
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err |= GETREG(regs, R11, from, r11);
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err |= GETREG(regs, R12, from, r12);
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err |= GETREG(regs, R13, from, r13);
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err |= GETREG(regs, R14, from, r14);
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err |= GETREG(regs, R15, from, r15);
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err |= GETREG(regs, RDI, from, rdi);
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err |= GETREG(regs, RSI, from, rsi);
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err |= GETREG(regs, RBP, from, rbp);
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err |= GETREG(regs, RBX, from, rbx);
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err |= GETREG(regs, RDX, from, rdx);
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err |= GETREG(regs, RAX, from, rax);
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err |= GETREG(regs, RCX, from, rcx);
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err |= GETREG(regs, RSP, from, rsp);
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err |= GETREG(regs, RIP, from, rip);
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err |= GETREG(regs, EFLAGS, from, eflags);
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err |= GETREG(regs, CS, from, cs);
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#undef GETREG
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return err;
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}
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int copy_sc_to_user_skas(struct sigcontext __user *to,
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struct _fpstate __user *to_fp,
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struct pt_regs *regs, unsigned long mask,
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unsigned long sp)
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{
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struct faultinfo * fi = ¤t->thread.arch.faultinfo;
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int err = 0;
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err |= __put_user(0, &to->gs);
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err |= __put_user(0, &to->fs);
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#define PUTREG(regs, regno, sc, regname) \
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__put_user((regs)->regs.skas.regs[(regno) / sizeof(unsigned long)], \
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&(sc)->regname)
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err |= PUTREG(regs, RDI, to, rdi);
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err |= PUTREG(regs, RSI, to, rsi);
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err |= PUTREG(regs, RBP, to, rbp);
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/* Must use orignal RSP, which is passed in, rather than what's in
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* the pt_regs, because that's already been updated to point at the
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* signal frame.
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*/
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err |= __put_user(sp, &to->rsp);
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err |= PUTREG(regs, RBX, to, rbx);
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err |= PUTREG(regs, RDX, to, rdx);
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err |= PUTREG(regs, RCX, to, rcx);
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err |= PUTREG(regs, RAX, to, rax);
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err |= PUTREG(regs, R8, to, r8);
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err |= PUTREG(regs, R9, to, r9);
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err |= PUTREG(regs, R10, to, r10);
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err |= PUTREG(regs, R11, to, r11);
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err |= PUTREG(regs, R12, to, r12);
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err |= PUTREG(regs, R13, to, r13);
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err |= PUTREG(regs, R14, to, r14);
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err |= PUTREG(regs, R15, to, r15);
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err |= PUTREG(regs, CS, to, cs); /* XXX x86_64 doesn't do this */
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err |= __put_user(fi->cr2, &to->cr2);
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err |= __put_user(fi->error_code, &to->err);
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err |= __put_user(fi->trap_no, &to->trapno);
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err |= PUTREG(regs, RIP, to, rip);
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err |= PUTREG(regs, EFLAGS, to, eflags);
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#undef PUTREG
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err |= __put_user(mask, &to->oldmask);
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return(err);
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}
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#endif
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#ifdef CONFIG_MODE_TT
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int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
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int fpsize)
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{
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struct _fpstate *to_fp;
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struct _fpstate __user *from_fp;
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unsigned long sigs;
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int err;
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to_fp = to->fpstate;
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sigs = to->oldmask;
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err = copy_from_user(to, from, sizeof(*to));
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from_fp = to->fpstate;
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to->fpstate = to_fp;
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to->oldmask = sigs;
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if(to_fp != NULL)
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err |= copy_from_user(to_fp, from_fp, fpsize);
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return(err);
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}
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int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
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struct sigcontext *from, int fpsize, unsigned long sp)
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{
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struct _fpstate __user *to_fp;
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struct _fpstate *from_fp;
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int err;
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to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
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from_fp = from->fpstate;
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err = copy_to_user(to, from, sizeof(*to));
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/* The SP in the sigcontext is the updated one for the signal
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* delivery. The sp passed in is the original, and this needs
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* to be restored, so we stick it in separately.
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*/
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err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
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if(from_fp != NULL){
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err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
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err |= copy_to_user(to_fp, from_fp, fpsize);
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}
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return err;
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}
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#endif
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static int copy_sc_from_user(struct pt_regs *to, void __user *from)
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{
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int ret;
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ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
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sizeof(struct _fpstate)),
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copy_sc_from_user_skas(to, from));
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return(ret);
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}
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static int copy_sc_to_user(struct sigcontext __user *to,
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struct _fpstate __user *fp,
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struct pt_regs *from, unsigned long mask,
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unsigned long sp)
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{
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return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
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sizeof(*fp), sp),
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copy_sc_to_user_skas(to, fp, from, mask, sp)));
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}
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struct rt_sigframe
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{
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char __user *pretcode;
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struct ucontext uc;
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struct siginfo info;
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};
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#define round_down(m, n) (((m) / (n)) * (n))
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int setup_signal_stack_si(unsigned long stack_top, int sig,
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struct k_sigaction *ka, struct pt_regs * regs,
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siginfo_t *info, sigset_t *set)
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{
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struct rt_sigframe __user *frame;
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struct _fpstate __user *fp = NULL;
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unsigned long save_sp = PT_REGS_RSP(regs);
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int err = 0;
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struct task_struct *me = current;
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frame = (struct rt_sigframe __user *)
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round_down(stack_top - sizeof(struct rt_sigframe), 16);
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/* Subtract 128 for a red zone and 8 for proper alignment */
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frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
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if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
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goto out;
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#if 0 /* XXX */
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if (save_i387(fp) < 0)
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err |= -1;
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#endif
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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goto out;
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if (ka->sa.sa_flags & SA_SIGINFO) {
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err |= copy_siginfo_to_user(&frame->info, info);
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if (err)
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goto out;
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}
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/* Update SP now because the page fault handler refuses to extend
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* the stack if the faulting address is too far below the current
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* SP, which frame now certainly is. If there's an error, the original
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* value is restored on the way out.
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* When writing the sigcontext to the stack, we have to write the
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* original value, so that's passed to copy_sc_to_user, which does
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* the right thing with it.
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*/
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PT_REGS_RSP(regs) = (unsigned long) frame;
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/* Create the ucontext. */
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err |= __put_user(0, &frame->uc.uc_flags);
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err |= __put_user(0, &frame->uc.uc_link);
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err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
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err |= __put_user(sas_ss_flags(save_sp),
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&frame->uc.uc_stack.ss_flags);
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err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
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err |= copy_sc_to_user(&frame->uc.uc_mcontext, fp, regs, set->sig[0],
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save_sp);
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err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
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if (sizeof(*set) == 16) {
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__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
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__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
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}
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else
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err |= __copy_to_user(&frame->uc.uc_sigmask, set,
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sizeof(*set));
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/* Set up to return from userspace. If provided, use a stub
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already in userspace. */
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/* x86-64 should always use SA_RESTORER. */
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if (ka->sa.sa_flags & SA_RESTORER)
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err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
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else
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/* could use a vstub here */
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goto restore_sp;
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if (err)
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goto restore_sp;
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/* Set up registers for signal handler */
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{
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struct exec_domain *ed = current_thread_info()->exec_domain;
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if (unlikely(ed && ed->signal_invmap && sig < 32))
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sig = ed->signal_invmap[sig];
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}
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PT_REGS_RDI(regs) = sig;
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/* In case the signal handler was declared without prototypes */
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PT_REGS_RAX(regs) = 0;
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/* This also works for non SA_SIGINFO handlers because they expect the
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next argument after the signal number on the stack. */
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PT_REGS_RSI(regs) = (unsigned long) &frame->info;
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PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
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PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
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out:
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return err;
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restore_sp:
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PT_REGS_RSP(regs) = save_sp;
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return err;
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}
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long sys_rt_sigreturn(struct pt_regs *regs)
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{
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unsigned long sp = PT_REGS_SP(¤t->thread.regs);
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struct rt_sigframe __user *frame =
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(struct rt_sigframe __user *)(sp - 8);
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struct ucontext __user *uc = &frame->uc;
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sigset_t set;
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if(copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
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goto segfault;
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sigdelsetmask(&set, ~_BLOCKABLE);
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spin_lock_irq(¤t->sighand->siglock);
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current->blocked = set;
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recalc_sigpending();
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spin_unlock_irq(¤t->sighand->siglock);
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if(copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext))
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goto segfault;
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/* Avoid ERESTART handling */
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PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
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return(PT_REGS_SYSCALL_RET(¤t->thread.regs));
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segfault:
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force_sig(SIGSEGV, current);
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return 0;
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}
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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