Skip to content

Commit

Permalink
MIPS: Move signal trampolines off of the stack.
Browse files Browse the repository at this point in the history 
This is a follow on to the vdso patch.

Since all processes now have signal trampolines permanently mapped, we
can use those instead of putting the trampoline on the stack and
invalidating the corresponding icache across all CPUs.  We also get rid
of a bunch of ICACHE_REFILLS_WORKAROUND_WAR code.

[Ralf: GDB 7.1 which has the necessary modifications to allow backtracing
over signal frames will supposedly be released tomorrow.  The old signal
frame format obsoleted by this patch exists in two variations, for sane
processors and for those requiring ICACHE_REFILLS_WORKAROUND_WAR.  So
there was never a GDB which did support backtracing over signal frames
on all MIPS systems.  This convinved me this series should be applied and
pushed upstream as soon as possible.]

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/974/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  • Loading branch information
David Daney authored and Ralf Baechle committed Apr 12, 2010
1 parent c52d0d3 commit d814c28
Show file tree
Hide file tree
Showing 5 changed files with 43 additions and 135 deletions.
6 changes: 4 additions & 2 deletions arch/mips/include/asm/abi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,12 +13,14 @@
#include <asm/siginfo.h>

struct mips_abi {
int (* const setup_frame)(struct k_sigaction * ka,
int (* const setup_frame)(void *sig_return, struct k_sigaction *ka,
struct pt_regs *regs, int signr,
sigset_t *set);
int (* const setup_rt_frame)(struct k_sigaction * ka,
const unsigned long signal_return_offset;
int (* const setup_rt_frame)(void *sig_return, struct k_sigaction *ka,
struct pt_regs *regs, int signr,
sigset_t *set, siginfo_t *info);
const unsigned long rt_signal_return_offset;
const unsigned long restart;
};

Expand Down
5 changes: 0 additions & 5 deletions arch/mips/kernel/signal-common.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,11 +26,6 @@
*/
extern void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
size_t frame_size);
/*
* install trampoline code to get back from the sig handler
*/
extern int install_sigtramp(unsigned int __user *tramp, unsigned int syscall);

/* Check and clear pending FPU exceptions in saved CSR */
extern int fpcsr_pending(unsigned int __user *fpcsr);

Expand Down
86 changes: 19 additions & 67 deletions arch/mips/kernel/signal.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#include <asm/ucontext.h>
#include <asm/cpu-features.h>
#include <asm/war.h>
#include <asm/vdso.h>

#include "signal-common.h"

Expand All @@ -44,47 +45,20 @@ extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);

/*
* Horribly complicated - with the bloody RM9000 workarounds enabled
* the signal trampolines is moving to the end of the structure so we can
* increase the alignment without breaking software compatibility.
*/
#if ICACHE_REFILLS_WORKAROUND_WAR == 0

struct sigframe {
u32 sf_ass[4]; /* argument save space for o32 */
u32 sf_code[2]; /* signal trampoline */
u32 sf_pad[2]; /* Was: signal trampoline */
struct sigcontext sf_sc;
sigset_t sf_mask;
};

struct rt_sigframe {
u32 rs_ass[4]; /* argument save space for o32 */
u32 rs_code[2]; /* signal trampoline */
u32 rs_pad[2]; /* Was: signal trampoline */
struct siginfo rs_info;
struct ucontext rs_uc;
};

#else

struct sigframe {
u32 sf_ass[4]; /* argument save space for o32 */
u32 sf_pad[2];
struct sigcontext sf_sc; /* hw context */
sigset_t sf_mask;
u32 sf_code[8] ____cacheline_aligned; /* signal trampoline */
};

struct rt_sigframe {
u32 rs_ass[4]; /* argument save space for o32 */
u32 rs_pad[2];
struct siginfo rs_info;
struct ucontext rs_uc;
u32 rs_code[8] ____cacheline_aligned; /* signal trampoline */
};

#endif

/*
* Helper routines
*/
Expand Down Expand Up @@ -266,32 +240,6 @@ void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
return (void __user *)((sp - frame_size) & (ICACHE_REFILLS_WORKAROUND_WAR ? ~(cpu_icache_line_size()-1) : ALMASK));
}

int install_sigtramp(unsigned int __user *tramp, unsigned int syscall)
{
int err;

/*
* Set up the return code ...
*
* li v0, __NR__foo_sigreturn
* syscall
*/

err = __put_user(0x24020000 + syscall, tramp + 0);
err |= __put_user(0x0000000c , tramp + 1);
if (ICACHE_REFILLS_WORKAROUND_WAR) {
err |= __put_user(0, tramp + 2);
err |= __put_user(0, tramp + 3);
err |= __put_user(0, tramp + 4);
err |= __put_user(0, tramp + 5);
err |= __put_user(0, tramp + 6);
err |= __put_user(0, tramp + 7);
}
flush_cache_sigtramp((unsigned long) tramp);

return err;
}

/*
* Atomically swap in the new signal mask, and wait for a signal.
*/
Expand Down Expand Up @@ -484,8 +432,8 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
}

#ifdef CONFIG_TRAD_SIGNALS
static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
int signr, sigset_t *set)
static int setup_frame(void *sig_return, struct k_sigaction *ka,
struct pt_regs *regs, int signr, sigset_t *set)
{
struct sigframe __user *frame;
int err = 0;
Expand All @@ -494,8 +442,6 @@ static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
goto give_sigsegv;

err |= install_sigtramp(frame->sf_code, __NR_sigreturn);

err |= setup_sigcontext(regs, &frame->sf_sc);
err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
if (err)
Expand All @@ -515,7 +461,7 @@ static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
regs->regs[ 5] = 0;
regs->regs[ 6] = (unsigned long) &frame->sf_sc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) frame->sf_code;
regs->regs[31] = (unsigned long) sig_return;
regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
Expand All @@ -529,8 +475,9 @@ static int setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
}
#endif

static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
int signr, sigset_t *set, siginfo_t *info)
static int setup_rt_frame(void *sig_return, struct k_sigaction *ka,
struct pt_regs *regs, int signr, sigset_t *set,
siginfo_t *info)
{
struct rt_sigframe __user *frame;
int err = 0;
Expand All @@ -539,8 +486,6 @@ static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
goto give_sigsegv;

err |= install_sigtramp(frame->rs_code, __NR_rt_sigreturn);

/* Create siginfo. */
err |= copy_siginfo_to_user(&frame->rs_info, info);

Expand Down Expand Up @@ -573,7 +518,7 @@ static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
regs->regs[ 5] = (unsigned long) &frame->rs_info;
regs->regs[ 6] = (unsigned long) &frame->rs_uc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) frame->rs_code;
regs->regs[31] = (unsigned long) sig_return;
regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
Expand All @@ -590,15 +535,20 @@ static int setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
struct mips_abi mips_abi = {
#ifdef CONFIG_TRAD_SIGNALS
.setup_frame = setup_frame,
.signal_return_offset = offsetof(struct mips_vdso, signal_trampoline),
#endif
.setup_rt_frame = setup_rt_frame,
.rt_signal_return_offset =
offsetof(struct mips_vdso, rt_signal_trampoline),
.restart = __NR_restart_syscall
};

static int handle_signal(unsigned long sig, siginfo_t *info,
struct k_sigaction *ka, sigset_t *oldset, struct pt_regs *regs)
{
int ret;
struct mips_abi *abi = current->thread.abi;
void *vdso = current->mm->context.vdso;

switch(regs->regs[0]) {
case ERESTART_RESTARTBLOCK:
Expand All @@ -619,9 +569,11 @@ static int handle_signal(unsigned long sig, siginfo_t *info,
regs->regs[0] = 0; /* Don't deal with this again. */

if (sig_uses_siginfo(ka))
ret = current->thread.abi->setup_rt_frame(ka, regs, sig, oldset, info);
ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset,
ka, regs, sig, oldset, info);
else
ret = current->thread.abi->setup_frame(ka, regs, sig, oldset);
ret = abi->setup_frame(vdso + abi->signal_return_offset,
ka, regs, sig, oldset);

spin_lock_irq(&current->sighand->siglock);
sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
Expand Down
55 changes: 14 additions & 41 deletions arch/mips/kernel/signal32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#include <asm/system.h>
#include <asm/fpu.h>
#include <asm/war.h>
#include <asm/vdso.h>

#include "signal-common.h"

Expand All @@ -47,8 +48,6 @@ extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user
/*
* Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
*/
#define __NR_O32_sigreturn 4119
#define __NR_O32_rt_sigreturn 4193
#define __NR_O32_restart_syscall 4253

/* 32-bit compatibility types */
Expand Down Expand Up @@ -77,47 +76,20 @@ struct ucontext32 {
compat_sigset_t uc_sigmask; /* mask last for extensibility */
};

/*
* Horribly complicated - with the bloody RM9000 workarounds enabled
* the signal trampolines is moving to the end of the structure so we can
* increase the alignment without breaking software compatibility.
*/
#if ICACHE_REFILLS_WORKAROUND_WAR == 0

struct sigframe32 {
u32 sf_ass[4]; /* argument save space for o32 */
u32 sf_code[2]; /* signal trampoline */
u32 sf_pad[2]; /* Was: signal trampoline */
struct sigcontext32 sf_sc;
compat_sigset_t sf_mask;
};

struct rt_sigframe32 {
u32 rs_ass[4]; /* argument save space for o32 */
u32 rs_code[2]; /* signal trampoline */
u32 rs_pad[2]; /* Was: signal trampoline */
compat_siginfo_t rs_info;
struct ucontext32 rs_uc;
};

#else /* ICACHE_REFILLS_WORKAROUND_WAR */

struct sigframe32 {
u32 sf_ass[4]; /* argument save space for o32 */
u32 sf_pad[2];
struct sigcontext32 sf_sc; /* hw context */
compat_sigset_t sf_mask;
u32 sf_code[8] ____cacheline_aligned; /* signal trampoline */
};

struct rt_sigframe32 {
u32 rs_ass[4]; /* argument save space for o32 */
u32 rs_pad[2];
compat_siginfo_t rs_info;
struct ucontext32 rs_uc;
u32 rs_code[8] __attribute__((aligned(32))); /* signal trampoline */
};

#endif /* !ICACHE_REFILLS_WORKAROUND_WAR */

/*
* sigcontext handlers
*/
Expand Down Expand Up @@ -598,8 +570,8 @@ asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
force_sig(SIGSEGV, current);
}

static int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
int signr, sigset_t *set)
static int setup_frame_32(void *sig_return, struct k_sigaction *ka,
struct pt_regs *regs, int signr, sigset_t *set)
{
struct sigframe32 __user *frame;
int err = 0;
Expand All @@ -608,8 +580,6 @@ static int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
goto give_sigsegv;

err |= install_sigtramp(frame->sf_code, __NR_O32_sigreturn);

err |= setup_sigcontext32(regs, &frame->sf_sc);
err |= __copy_conv_sigset_to_user(&frame->sf_mask, set);

Expand All @@ -630,7 +600,7 @@ static int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
regs->regs[ 5] = 0;
regs->regs[ 6] = (unsigned long) &frame->sf_sc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) frame->sf_code;
regs->regs[31] = (unsigned long) sig_return;
regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
Expand All @@ -644,8 +614,9 @@ static int setup_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
return -EFAULT;
}

static int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
int signr, sigset_t *set, siginfo_t *info)
static int setup_rt_frame_32(void *sig_return, struct k_sigaction *ka,
struct pt_regs *regs, int signr, sigset_t *set,
siginfo_t *info)
{
struct rt_sigframe32 __user *frame;
int err = 0;
Expand All @@ -655,8 +626,6 @@ static int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
goto give_sigsegv;

err |= install_sigtramp(frame->rs_code, __NR_O32_rt_sigreturn);

/* Convert (siginfo_t -> compat_siginfo_t) and copy to user. */
err |= copy_siginfo_to_user32(&frame->rs_info, info);

Expand Down Expand Up @@ -690,7 +659,7 @@ static int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
regs->regs[ 5] = (unsigned long) &frame->rs_info;
regs->regs[ 6] = (unsigned long) &frame->rs_uc;
regs->regs[29] = (unsigned long) frame;
regs->regs[31] = (unsigned long) frame->rs_code;
regs->regs[31] = (unsigned long) sig_return;
regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
Expand All @@ -709,7 +678,11 @@ static int setup_rt_frame_32(struct k_sigaction * ka, struct pt_regs *regs,
*/
struct mips_abi mips_abi_32 = {
.setup_frame = setup_frame_32,
.signal_return_offset =
offsetof(struct mips_vdso, o32_signal_trampoline),
.setup_rt_frame = setup_rt_frame_32,
.rt_signal_return_offset =
offsetof(struct mips_vdso, o32_rt_signal_trampoline),
.restart = __NR_O32_restart_syscall
};

Expand Down
Loading

0 comments on commit d814c28

Please sign in to comment.