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authorGuo Ren <guoren@linux.alibaba.com>2021-09-24 15:33:38 +0800
committerGuo Ren <guoren@linux.alibaba.com>2021-10-16 07:20:12 +0800
commitaf89ebaa64de726ca0a39bbb0bf0c81a1f43ad50 (patch)
tree42259e29611ea2266daeedb158aae45af783ba85 /arch/csky
parentfbd63c08cdcca5fb1315aca3172b3c9c272cfb4f (diff)
downloadlinux-af89ebaa64de726ca0a39bbb0bf0c81a1f43ad50.tar.bz2
csky: Fixup regs.sr broken in ptrace
gpr_get() return the entire pt_regs (include sr) to userspace, if we don't restore the C bit in gpr_set, it may break the ALU result in that context. So the C flag bit is part of gpr context, that's why riscv totally remove the C bit in the ISA. That makes sr reg clear from userspace to supervisor privilege. Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org
Diffstat (limited to 'arch/csky')
-rw-r--r--arch/csky/kernel/ptrace.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c
index 0105ac81b432..1a5f54e0d272 100644
--- a/arch/csky/kernel/ptrace.c
+++ b/arch/csky/kernel/ptrace.c
@@ -99,7 +99,8 @@ static int gpr_set(struct task_struct *target,
if (ret)
return ret;
- regs.sr = task_pt_regs(target)->sr;
+ /* BIT(0) of regs.sr is Condition Code/Carry bit */
+ regs.sr = (regs.sr & BIT(0)) | (task_pt_regs(target)->sr & ~BIT(0));
#ifdef CONFIG_CPU_HAS_HILO
regs.dcsr = task_pt_regs(target)->dcsr;
#endif