[PATCHv2 1/7] arm64: Add ASM_BUG()
From: mark.rutland@arm.com (Mark Rutland)
Date: 2017-08-09 13:21:31
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
On Wed, Aug 09, 2017 at 11:07:35AM +0100, Catalin Marinas wrote:
On Tue, Aug 08, 2017 at 05:10:51PM +0100, Mark Rutland wrote:quoted
On Tue, Aug 08, 2017 at 04:58:53PM +0100, Catalin Marinas wrote:quoted
I'll pull arm64/exception-stack into for-next/core (I haven't got to the vmap-stack series yet).If you could hold off for a day, I'd like to make one final change and prevent use of the final record's LR value, where FP is NULL, since that LR isn't meaningful, and makes the backtrace look weird: [ 2785.650646] [<ffff000008082cb0>] el0_svc_naked+0x24/0x28 [ 2785.656016] [<0000ffffaf717554>] 0xffffaf717554 Otherwise, I can do that as a fixup.I'll hold off, I haven't pushed the for-next/core branch out yet.
I've pushed out an updated arm64/exception-stack branch. The HEAD should
be:
31e43ad3b74a5d7b ("arm64: unwind: remove sp from struct stackframe")
That should have tvhe ASM_BUG() fix, and the below diff folded into the
pt_regs patch, to ensure that backtraces don't use user-controlled PCs
or idmap aliases of startup code.
If you'd like, I can send the updated series as a v3.
Thanks,
Mark.
---->8----diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 4ddb8d7..612a077 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S@@ -116,7 +116,11 @@ * time the exception was taken (in case we attempt to walk the call * stack later), chain it together with the stack frames. */ + .if \el == 0 + stp xzr, xzr, [sp, #S_STACKFRAME] + .else stp x29, x22, [sp, #S_STACKFRAME] + .endif add x29, sp, #S_STACKFRAME #ifdef CONFIG_ARM64_SW_TTBR0_PAN
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 973df7d..f9e4aac 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S@@ -362,6 +362,9 @@ __primary_switched: ret // to __primary_switch() 0: #endif + add sp, sp, #16 + mov x29, #0 + mov x30, #0 b start_kernel ENDPROC(__primary_switched)
@@ -617,6 +620,7 @@ __secondary_switched: ldr x2, [x0, #CPU_BOOT_TASK] msr sp_el0, x2 mov x29, #0 + mov x30, #0 b secondary_start_kernel ENDPROC(__secondary_switched)
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 54f3463..35588ca 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c@@ -74,6 +74,15 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + /* + * Frames created upon entry from EL0 have NULL FP and PC values, so + * don't bother reporting these. Frames created by __noreturn functions + * might have a valid FP even if PC is bogus, so only terminate where + * both are NULL. + */ + if (!frame->fp && !frame->pc) + return -EINVAL; + return 0; }
--
1.9.1