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authorArd Biesheuvel <ardb@kernel.org>2021-10-05 09:15:40 +0200
committerArd Biesheuvel <ardb@kernel.org>2021-12-03 15:11:31 +0100
commitd4664b6c987f80338407889c1e3f3abe7e16be94 (patch)
tree21565f50f64551f10a68d2df793711ac07962c53 /arch/arm/lib/backtrace.S
parenteae9523fdd7a6c592e80666681962acbd913cda2 (diff)
downloadlinux-d4664b6c987f80338407889c1e3f3abe7e16be94.tar.bz2
ARM: implement IRQ stacks
Now that we no longer rely on the stack pointer to access the current task struct or thread info, we can implement support for IRQ stacks cleanly as well. Define a per-CPU IRQ stack and switch to this stack when taking an IRQ, provided that we were not already using that stack in the interrupted context. This is never the case for IRQs taken from user space, but ones taken while running in the kernel could fire while one taken from user space has not completed yet. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Keith Packard <keithpac@amazon.com> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Marc Zyngier <maz@kernel.org> Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Diffstat (limited to 'arch/arm/lib/backtrace.S')
-rw-r--r--arch/arm/lib/backtrace.S8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S
index e8408f22d4dc..293a2716bd20 100644
--- a/arch/arm/lib/backtrace.S
+++ b/arch/arm/lib/backtrace.S
@@ -98,6 +98,14 @@ for_each_frame: tst frame, mask @ Check for address exceptions
cmp sv_fp, frame @ next frame must be
mov frame, sv_fp @ above the current frame
+#ifdef CONFIG_IRQSTACKS
+ @
+ @ Kernel stacks may be discontiguous in memory. If the next
+ @ frame is below the previous frame, accept it as long as it
+ @ lives in kernel memory.
+ @
+ cmpls sv_fp, #PAGE_OFFSET
+#endif
bhi for_each_frame
1006: adr r0, .Lbad