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| author | Dave P Martin <Dave.Martin@arm.com> | 2015-07-24 15:37:48 (GMT) |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-07-27 10:08:42 (GMT) |
| commit | 9fb7410f955f7a62c1f882ca8f9ffd4525907e28 (patch) | |
| tree | 1a3da5d5b35c0cff97fea27331cdd25e7bd58c58 /arch/arm64/include/asm/debug-monitors.h | |
| parent | d7a33f4fbd12ca0a32a24cc46c0d02b47f6b54d1 (diff) | |
| download | linux-9fb7410f955f7a62c1f882ca8f9ffd4525907e28.tar.xz | |
arm64/BUG: Use BRK instruction for generic BUG traps
Currently, the minimal default BUG() implementation from asm-
generic is used for arm64.
This patch uses the BRK software breakpoint instruction to generate
a trap instead, similarly to most other arches, with the generic
BUG code generating the dmesg boilerplate.
This allows bug metadata to be moved to a separate table and
reduces the amount of inline code at BUG and WARN sites. This also
avoids clobbering any registers before they can be dumped.
To mitigate the size of the bug table further, this patch makes
use of the existing infrastructure for encoding addresses within
the bug table as 32-bit offsets instead of absolute pointers.
(Note that this limits the kernel size to 2GB.)
Traps are registered at arch_initcall time for aarch64, but BUG
has minimal real dependencies and it is desirable to be able to
generate bug splats as early as possible. This patch redirects
all debug exceptions caused by BRK directly to bug_handler() until
the full debug exception support has been initialised.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/debug-monitors.h')
| -rw-r--r-- | arch/arm64/include/asm/debug-monitors.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h index 777c36a..e3f2bad 100644 --- a/arch/arm64/include/asm/debug-monitors.h +++ b/arch/arm64/include/asm/debug-monitors.h @@ -52,10 +52,12 @@ * 0x100: for triggering a fault on purpose (reserved) * 0x400: for dynamic BRK instruction * 0x401: for compile time BRK instruction + * 0x800: kernel-mode BUG() and WARN() traps */ #define FAULT_BRK_IMM 0x100 #define KGDB_DYN_DBG_BRK_IMM 0x400 #define KGDB_COMPILED_DBG_BRK_IMM 0x401 +#define BUG_BRK_IMM 0x800 /* * BRK instruction encoding |