leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

arm: Add syscall detection for restartable sequences

Browse Source 
Syscalls are not allowed inside restartable sequences, so add a call to
rseq_syscall() at the very beginning of system call exiting path for
CONFIG_DEBUG_RSEQ=y kernel. This could help us to detect whether there
is a syscall issued inside restartable sequences.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Watson <davejwatson@fb.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Chris Lameter <cl@linux.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Hunter <ahh@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Maurer <bmaurer@fb.com>
Cc: linux-api@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20180602124408.8430-5-mathieu.desnoyers@efficios.com
This commit is contained in:
Mathieu Desnoyers 2018-06-02 08:43:56 -04:00 committed by Thomas Gleixner
parent 9800b9dc13
commit b74406f377
2 changed files with 26 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
arch/arm/kernel/entry-common.S
View File

@ -39,12 +39,13 @@ saved_pc .req lr
.section .entry.text,"ax",%progbits
.align 5
#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING) || \
IS_ENABLED(CONFIG_DEBUG_RSEQ))
/*
* This is the fast syscall return path. We do as little as possible here,
* such as avoiding writing r0 to the stack. We only use this path if we
* have tracing and context tracking disabled - the overheads from those
* features make this path too inefficient.
* have tracing, context tracking and rseq debug disabled - the overheads
* from those features make this path too inefficient.
*/
ret_fast_syscall:
UNWIND(.fnstart )
@ -71,14 +72,20 @@ fast_work_pending:
/* fall through to work_pending */
#else
/*
* The "replacement" ret_fast_syscall for when tracing or context tracking
* is enabled. As we will need to call out to some C functions, we save
* r0 first to avoid needing to save registers around each C function call.
* The "replacement" ret_fast_syscall for when tracing, context tracking,
* or rseq debug is enabled. As we will need to call out to some C functions,
* we save r0 first to avoid needing to save registers around each C function
* call.
*/
ret_fast_syscall:
UNWIND(.fnstart )
UNWIND(.cantunwind )
str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
#if IS_ENABLED(CONFIG_DEBUG_RSEQ)
/* do_rseq_syscall needs interrupts enabled. */
mov r0, sp @ 'regs'
bl do_rseq_syscall
#endif
disable_irq_notrace @ disable interrupts
ldr r2, [tsk, #TI_ADDR_LIMIT]
cmp r2, #TASK_SIZE
@ -113,6 +120,12 @@ ENDPROC(ret_fast_syscall)
*/
ENTRY(ret_to_user)
ret_slow_syscall:
#if IS_ENABLED(CONFIG_DEBUG_RSEQ)
/* do_rseq_syscall needs interrupts enabled. */
enable_irq_notrace @ enable interrupts
mov r0, sp @ 'regs'
bl do_rseq_syscall
#endif
disable_irq_notrace @ disable interrupts
ENTRY(ret_to_user_from_irq)
ldr r2, [tsk, #TI_ADDR_LIMIT]

7
arch/arm/kernel/signal.c
View File

@ -710,3 +710,10 @@ asmlinkage void addr_limit_check_failed(void)
{
addr_limit_user_check();
}
#ifdef CONFIG_DEBUG_RSEQ
asmlinkage void do_rseq_syscall(struct pt_regs *regs)
{
rseq_syscall(regs);
}
#endif