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[PATCH] [ARM] Clear reserved bits in CPSR
- From: Yao Qi <qiyaoltc at gmail dot com>
- To: gdb-patches at sourceware dot org
- Date: Fri, 22 Apr 2016 11:24:14 +0100
- Subject: [PATCH] [ARM] Clear reserved bits in CPSR
- Authentication-results: sourceware.org; auth=none
Bits 20 ~ 23 of CPSR are reserved (RAZ, read as zero), but they are not
zero if the arm program runs on aarch64-linux. AArch64 tracer gets PSTATE
from arm 32-bit tracee as CPSR, but bits 20 ~ 23 are used in PSTATE. I
think kernel should clear these bits when it is read through ptrace, but
the fix in user space is still needed.
This patch fixes these two fails,
-FAIL: gdb.reverse/insn-reverse.exp: ext_reg_push_pop: compare registers on insn 0:vldr d7, [r11, #-12]
-FAIL: gdb.reverse/insn-reverse.exp: ext_reg_push_pop: compare registers on insn 0:vldr d7, [r7]
Regression tested on both native and remote on aarch64-linux.
gdb:
2016-04-22 Yao Qi <yao.qi@linaro.org>
* aarch32-linux-nat.c (aarch32_gp_regcache_supply): Clear CPSR
bits 20 to 23.
gdb/gdbserver:
2016-04-22 Yao Qi <yao.qi@linaro.org>
* linux-aarch32-low.c (arm_store_gregset): Clear CPSR bits 20
to 23.
---
gdb/aarch32-linux-nat.c | 6 +++++-
gdb/gdbserver/linux-aarch32-low.c | 5 ++++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/gdb/aarch32-linux-nat.c b/gdb/aarch32-linux-nat.c
index 568dfa6..97b319b 100644
--- a/gdb/aarch32-linux-nat.c
+++ b/gdb/aarch32-linux-nat.c
@@ -37,7 +37,11 @@ aarch32_gp_regcache_supply (struct regcache *regcache, uint32_t *regs,
regcache_raw_supply (regcache, regno, ®s[regno]);
if (arm_apcs_32)
- regcache_raw_supply (regcache, ARM_PS_REGNUM, ®s[ARM_CPSR_GREGNUM]);
+ {
+ /* Clear reserved bits bit 20 to bit 23. */
+ regs[ARM_CPSR_GREGNUM] = 0xff0fffff & regs[ARM_CPSR_GREGNUM];
+ regcache_raw_supply (regcache, ARM_PS_REGNUM, ®s[ARM_CPSR_GREGNUM]);
+ }
else
regcache_raw_supply (regcache, ARM_PS_REGNUM, ®s[ARM_PC_REGNUM]);
diff --git a/gdb/gdbserver/linux-aarch32-low.c b/gdb/gdbserver/linux-aarch32-low.c
index 0c4b140..5087550 100644
--- a/gdb/gdbserver/linux-aarch32-low.c
+++ b/gdb/gdbserver/linux-aarch32-low.c
@@ -77,6 +77,7 @@ arm_store_gregset (struct regcache *regcache, const void *buf)
int i;
char zerobuf[8];
const uint32_t *regs = (const uint32_t *) buf;
+ uint32_t cpsr = regs[ARM_CPSR_GREGNUM];
memset (zerobuf, 0, 8);
for (i = ARM_A1_REGNUM; i <= ARM_PC_REGNUM; i++)
@@ -85,7 +86,9 @@ arm_store_gregset (struct regcache *regcache, const void *buf)
for (; i < ARM_PS_REGNUM; i++)
supply_register (regcache, i, zerobuf);
- supply_register (regcache, ARM_PS_REGNUM, ®s[ARM_CPSR_GREGNUM]);
+ /* Clear reserved bits bit 20 to bit 23. */
+ cpsr = 0xff0fffff & cpsr;
+ supply_register (regcache, ARM_PS_REGNUM, &cpsr);
}
/* Collect NUM number of VFP registers from REGCACHE to buffer BUF. */
--
1.9.1