Commit 02a6ec6a authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'audit' of git://git.linaro.org/people/rmk/linux-arm

Pull ARM audit/signal updates from Russell King:
 "ARM audit/signal handling updates from Al and Will.  This improves on
  the work Viro did last merge window, and sorts out some of the issues
  found with that work."

* 'audit' of git://git.linaro.org/people/rmk/linux-arm:
  ARM: 7475/1: sys_trace: allow all syscall arguments to be updated via ptrace
  ARM: 7474/1: get rid of TIF_SYSCALL_RESTARTSYS
  ARM: 7473/1: deal with handlerless restarts without leaving the kernel
  ARM: 7472/1: pull all work_pending logics into C function
  ARM: 7471/1: Revert "7442/1: Revert "remove unused restart trampoline""
  ARM: 7470/1: Revert "7443/1: Revert "new way of handling ERESTART_RESTARTBLOCK""
parents 9a2533c3 c7aa00db
...@@ -51,23 +51,15 @@ ret_fast_syscall: ...@@ -51,23 +51,15 @@ ret_fast_syscall:
fast_work_pending: fast_work_pending:
str r0, [sp, #S_R0+S_OFF]! @ returned r0 str r0, [sp, #S_R0+S_OFF]! @ returned r0
work_pending: work_pending:
tst r1, #_TIF_NEED_RESCHED
bne work_resched
/*
* TIF_SIGPENDING or TIF_NOTIFY_RESUME must've been set if we got here
*/
ldr r2, [sp, #S_PSR]
mov r0, sp @ 'regs' mov r0, sp @ 'regs'
tst r2, #15 @ are we returning to user mode?
bne no_work_pending @ no? just leave, then...
mov r2, why @ 'syscall' mov r2, why @ 'syscall'
tst r1, #_TIF_SIGPENDING @ delivering a signal? bl do_work_pending
movne why, #0 @ prevent further restarts cmp r0, #0
bl do_notify_resume beq no_work_pending
b ret_slow_syscall @ Check work again movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
ldmia sp, {r0 - r6} @ have to reload r0 - r6
b local_restart @ ... and off we go
work_resched:
bl schedule
/* /*
* "slow" syscall return path. "why" tells us if this was a real syscall. * "slow" syscall return path. "why" tells us if this was a real syscall.
*/ */
...@@ -409,6 +401,7 @@ ENTRY(vector_swi) ...@@ -409,6 +401,7 @@ ENTRY(vector_swi)
eor scno, scno, #__NR_SYSCALL_BASE @ check OS number eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
#endif #endif
local_restart:
ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing
stmdb sp!, {r4, r5} @ push fifth and sixth args stmdb sp!, {r4, r5} @ push fifth and sixth args
...@@ -450,7 +443,8 @@ __sys_trace: ...@@ -450,7 +443,8 @@ __sys_trace:
mov scno, r0 @ syscall number (possibly new) mov scno, r0 @ syscall number (possibly new)
add r1, sp, #S_R0 + S_OFF @ pointer to regs add r1, sp, #S_R0 + S_OFF @ pointer to regs
cmp scno, #NR_syscalls @ check upper syscall limit cmp scno, #NR_syscalls @ check upper syscall limit
ldmccia r1, {r0 - r3} @ have to reload r0 - r3 ldmccia r1, {r0 - r6} @ have to reload r0 - r6
stmccia sp, {r4, r5} @ and update the stack args
ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
b 2b b 2b
......
...@@ -25,6 +25,7 @@ ...@@ -25,6 +25,7 @@
#include <linux/regset.h> #include <linux/regset.h>
#include <linux/audit.h> #include <linux/audit.h>
#include <linux/tracehook.h> #include <linux/tracehook.h>
#include <linux/unistd.h>
#include <asm/pgtable.h> #include <asm/pgtable.h>
#include <asm/traps.h> #include <asm/traps.h>
......
...@@ -27,7 +27,6 @@ ...@@ -27,7 +27,6 @@
*/ */
#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE)) #define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE)) #define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
#define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE)
/* /*
* With EABI, the syscall number has to be loaded into r7. * With EABI, the syscall number has to be loaded into r7.
...@@ -47,18 +46,6 @@ const unsigned long sigreturn_codes[7] = { ...@@ -47,18 +46,6 @@ const unsigned long sigreturn_codes[7] = {
MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN, MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
}; };
/*
* Either we support OABI only, or we have EABI with the OABI
* compat layer enabled. In the later case we don't know if
* user space is EABI or not, and if not we must not clobber r7.
* Always using the OABI syscall solves that issue and works for
* all those cases.
*/
const unsigned long syscall_restart_code[2] = {
SWI_SYS_RESTART, /* swi __NR_restart_syscall */
0xe49df004, /* ldr pc, [sp], #4 */
};
/* /*
* atomically swap in the new signal mask, and wait for a signal. * atomically swap in the new signal mask, and wait for a signal.
*/ */
...@@ -582,12 +569,13 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, ...@@ -582,12 +569,13 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
* the kernel can handle, and then we build all the user-level signal handling * the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that. * stack-frames in one go after that.
*/ */
static void do_signal(struct pt_regs *regs, int syscall) static int do_signal(struct pt_regs *regs, int syscall)
{ {
unsigned int retval = 0, continue_addr = 0, restart_addr = 0; unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
struct k_sigaction ka; struct k_sigaction ka;
siginfo_t info; siginfo_t info;
int signr; int signr;
int restart = 0;
/* /*
* If we were from a system call, check for system call restarting... * If we were from a system call, check for system call restarting...
...@@ -602,15 +590,15 @@ static void do_signal(struct pt_regs *regs, int syscall) ...@@ -602,15 +590,15 @@ static void do_signal(struct pt_regs *regs, int syscall)
* debugger will see the already changed PSW. * debugger will see the already changed PSW.
*/ */
switch (retval) { switch (retval) {
case -ERESTART_RESTARTBLOCK:
restart -= 2;
case -ERESTARTNOHAND: case -ERESTARTNOHAND:
case -ERESTARTSYS: case -ERESTARTSYS:
case -ERESTARTNOINTR: case -ERESTARTNOINTR:
restart++;
regs->ARM_r0 = regs->ARM_ORIG_r0; regs->ARM_r0 = regs->ARM_ORIG_r0;
regs->ARM_pc = restart_addr; regs->ARM_pc = restart_addr;
break; break;
case -ERESTART_RESTARTBLOCK:
regs->ARM_r0 = -EINTR;
break;
} }
} }
...@@ -619,14 +607,17 @@ static void do_signal(struct pt_regs *regs, int syscall) ...@@ -619,14 +607,17 @@ static void do_signal(struct pt_regs *regs, int syscall)
* point the debugger may change all our registers ... * point the debugger may change all our registers ...
*/ */
signr = get_signal_to_deliver(&info, &ka, regs, NULL); signr = get_signal_to_deliver(&info, &ka, regs, NULL);
if (signr > 0) {
/* /*
* Depending on the signal settings we may need to revert the * Depending on the signal settings we may need to revert the
* decision to restart the system call. But skip this if a * decision to restart the system call. But skip this if a
* debugger has chosen to restart at a different PC. * debugger has chosen to restart at a different PC.
*/ */
if (regs->ARM_pc == restart_addr) { if (regs->ARM_pc != restart_addr)
if (retval == -ERESTARTNOHAND restart = 0;
if (signr > 0) {
if (unlikely(restart)) {
if (retval == -ERESTARTNOHAND ||
retval == -ERESTART_RESTARTBLOCK
|| (retval == -ERESTARTSYS || (retval == -ERESTARTSYS
&& !(ka.sa.sa_flags & SA_RESTART))) { && !(ka.sa.sa_flags & SA_RESTART))) {
regs->ARM_r0 = -EINTR; regs->ARM_r0 = -EINTR;
...@@ -635,52 +626,43 @@ static void do_signal(struct pt_regs *regs, int syscall) ...@@ -635,52 +626,43 @@ static void do_signal(struct pt_regs *regs, int syscall)
} }
handle_signal(signr, &ka, &info, regs); handle_signal(signr, &ka, &info, regs);
return; return 0;
}
if (syscall) {
/*
* Handle restarting a different system call. As above,
* if a debugger has chosen to restart at a different PC,
* ignore the restart.
*/
if (retval == -ERESTART_RESTARTBLOCK
&& regs->ARM_pc == continue_addr) {
if (thumb_mode(regs)) {
regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
regs->ARM_pc -= 2;
} else {
#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT)
regs->ARM_r7 = __NR_restart_syscall;
regs->ARM_pc -= 4;
#else
u32 __user *usp;
regs->ARM_sp -= 4;
usp = (u32 __user *)regs->ARM_sp;
if (put_user(regs->ARM_pc, usp) == 0) {
regs->ARM_pc = KERN_RESTART_CODE;
} else {
regs->ARM_sp += 4;
force_sigsegv(0, current);
}
#endif
}
}
} }
restore_saved_sigmask(); restore_saved_sigmask();
if (unlikely(restart))
regs->ARM_pc = continue_addr;
return restart;
} }
asmlinkage void asmlinkage int
do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
{ {
if (thread_flags & _TIF_SIGPENDING) do {
do_signal(regs, syscall); if (likely(thread_flags & _TIF_NEED_RESCHED)) {
schedule();
if (thread_flags & _TIF_NOTIFY_RESUME) { } else {
if (unlikely(!user_mode(regs)))
return 0;
local_irq_enable();
if (thread_flags & _TIF_SIGPENDING) {
int restart = do_signal(regs, syscall);
if (unlikely(restart)) {
/*
* Restart without handlers.
* Deal with it without leaving
* the kernel space.
*/
return restart;
}
syscall = 0;
} else {
clear_thread_flag(TIF_NOTIFY_RESUME); clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs); tracehook_notify_resume(regs);
} }
}
local_irq_disable();
thread_flags = current_thread_info()->flags;
} while (thread_flags & _TIF_WORK_MASK);
return 0;
} }
...@@ -8,7 +8,5 @@ ...@@ -8,7 +8,5 @@
* published by the Free Software Foundation. * published by the Free Software Foundation.
*/ */
#define KERN_SIGRETURN_CODE (CONFIG_VECTORS_BASE + 0x00000500) #define KERN_SIGRETURN_CODE (CONFIG_VECTORS_BASE + 0x00000500)
#define KERN_RESTART_CODE (KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))
extern const unsigned long sigreturn_codes[7]; extern const unsigned long sigreturn_codes[7];
extern const unsigned long syscall_restart_code[2];
...@@ -844,8 +844,6 @@ void __init early_trap_init(void *vectors_base) ...@@ -844,8 +844,6 @@ void __init early_trap_init(void *vectors_base)
*/ */
memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE), memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),
sigreturn_codes, sizeof(sigreturn_codes)); sigreturn_codes, sizeof(sigreturn_codes));
memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),
syscall_restart_code, sizeof(syscall_restart_code));
flush_icache_range(vectors, vectors + PAGE_SIZE); flush_icache_range(vectors, vectors + PAGE_SIZE);
modify_domain(DOMAIN_USER, DOMAIN_CLIENT); modify_domain(DOMAIN_USER, DOMAIN_CLIENT);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment