arm64: opcodes.h: Add arm big-endian config options before including arm header

PATCH New James Morse 2 participants 2 messages Mar 24, 2016 – Mar 25, 2016 arm64

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James Morse

author

2016-03-24 16:54 UTC #0 lore raw

PATCH 1/1 arm64: opcodes.h: Add arm big-endian config options before including arm header

arm and arm64 use different config options to specify big endian. This needs taking into account when including code/headers between the two architectures.

A case in point is PAN, which uses the __instr_arm() macro to output instructions. The macro comes from opcodes.h, which lives under arch/arm. On a big-endian build the mismatched config options mean the instruction isn't byte swapped correctly, resulting in undefined instruction exceptions during boot:

Quoted 19 lines

alternatives: patching kernel code kdevtmpfs[87]: undefined instruction: pc=ffffffc0004505b4 kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c
Internal error: Oops - undefined instruction: 0 [#1] SMP
Modules linked in:
CPU: 0 PID: 87 Comm: kdevtmpfs Not tainted 4.1.16+ #5
Hardware name: Hisilicon PhosphorHi1382 EVB (DT)
task: ffffffc336591700 ti: ffffffc3365a4000 task.ti: ffffffc3365a4000
PC is at dump_instr+0x68/0x100
LR is at do_undefinstr+0x1d4/0x2a4
pc : [<ffffffc00076231c>] lr : [<ffffffc0000811d4>] pstate: 604001c5

Quoted 1 line

sp : ffffffc3365a6450

Reported-by Hanjun Guo <[email protected]>

Signed-off-by James Morse <[email protected]>

Cc <[email protected]> #4.3.x-

---
 arch/arm64/include/asm/opcodes.h | 4 ++++
 1 file changed, 4 insertions(+)

arch/arm64/include/asm/opcodes.h +4 -0

index 4e603ea36ad3..123f45d92cd1 100644
@@ -1 +1,5 @@
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define CONFIG_CPU_ENDIAN_BE8 CONFIG_CPU_BIG_ENDIAN
+#endif
+
 #include <../../arm/include/asm/opcodes.h>

Signature · 1 line

2.8.0.rc3

Hanjun Guo

2016-03-25 07:06 UTC #1 lore raw

PATCH 1/1 arm64: opcodes.h: Add arm big-endian config options before including arm header

Quoted 29 lines · James Morse

arm and arm64 use different config options to specify big endian. This needs taking into account when including code/headers between the two architectures.
A case in point is PAN, which uses the __instr_arm() macro to output instructions. The macro comes from opcodes.h, which lives under arch/arm. On a big-endian build the mismatched config options mean the instruction isn't byte swapped correctly, resulting in undefined instruction exceptions during boot:
Quoted 19 lines
alternatives: patching kernel code kdevtmpfs[87]: undefined instruction: pc=ffffffc0004505b4 kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c kdevtmpfs[87]: undefined instruction: pc=ffffffc00076231c
Internal error: Oops - undefined instruction: 0 [#1] SMP
Modules linked in:
CPU: 0 PID: 87 Comm: kdevtmpfs Not tainted 4.1.16+ #5
Hardware name: Hisilicon PhosphorHi1382 EVB (DT)
task: ffffffc336591700 ti: ffffffc3365a4000 task.ti: ffffffc3365a4000
PC is at dump_instr+0x68/0x100
LR is at do_undefinstr+0x1d4/0x2a4
pc : [<ffffffc00076231c>] lr : [<ffffffc0000811d4>] pstate: 604001c5
Quoted 1 line
sp : ffffffc3365a6450

Quoted 1 line

Reported-by Hanjun Guo <[email protected]>

My colleague Xuefeng helped to test this patch, and the bug reported is gone,

Tested-by Xuefeng Wang <[email protected]>

Thanks
Hanjun