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Message-Id: <b8d6ae4483fcfd17524e79d803c969694a85cc02.1687428075.git.christophe.leroy@csgroup.eu>
Date: Thu, 22 Jun 2023 12:01:23 +0200
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>,
linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2] powerpc/ptrace: Split gpr32_set_common
objtool report the following warning:
arch/powerpc/kernel/ptrace/ptrace-view.o: warning: objtool:
gpr32_set_common+0x23c (.text+0x860): redundant UACCESS disable
gpr32_set_common() conditionnaly opens and closes UACCESS based on
whether kbuf point is NULL or not. This is wackelig.
Split gpr32_set_common() in two fonctions, one for user one for
kernel.
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
v2: Mark gpr32_set_common_kernel() and gpr32_set_common_user() static
---
arch/powerpc/kernel/ptrace/ptrace-view.c | 106 ++++++++++++++---------
1 file changed, 67 insertions(+), 39 deletions(-)
diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c b/arch/powerpc/kernel/ptrace/ptrace-view.c
index 3910cd7bb2d9..42abbed452cd 100644
--- a/arch/powerpc/kernel/ptrace/ptrace-view.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-view.c
@@ -716,73 +716,89 @@ int gpr32_get_common(struct task_struct *target,
return membuf_zero(&to, (ELF_NGREG - PT_REGS_COUNT) * sizeof(u32));
}
-int gpr32_set_common(struct task_struct *target,
- const struct user_regset *regset,
- unsigned int pos, unsigned int count,
- const void *kbuf, const void __user *ubuf,
- unsigned long *regs)
+static int gpr32_set_common_kernel(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, unsigned long *regs)
{
const compat_ulong_t *k = kbuf;
+
+ pos /= sizeof(compat_ulong_t);
+ count /= sizeof(compat_ulong_t);
+
+ for (; count > 0 && pos < PT_MSR; --count)
+ regs[pos++] = *k++;
+
+ if (count > 0 && pos == PT_MSR) {
+ set_user_msr(target, *k++);
+ ++pos;
+ --count;
+ }
+
+ for (; count > 0 && pos <= PT_MAX_PUT_REG; --count)
+ regs[pos++] = *k++;
+ for (; count > 0 && pos < PT_TRAP; --count, ++pos)
+ ++k;
+
+ if (count > 0 && pos == PT_TRAP) {
+ set_user_trap(target, *k++);
+ ++pos;
+ --count;
+ }
+
+ kbuf = k;
+ pos *= sizeof(compat_ulong_t);
+ count *= sizeof(compat_ulong_t);
+ user_regset_copyin_ignore(&pos, &count, &kbuf, NULL,
+ (PT_TRAP + 1) * sizeof(compat_ulong_t), -1);
+ return 0;
+}
+
+static int gpr32_set_common_user(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void __user *ubuf, unsigned long *regs)
+{
const compat_ulong_t __user *u = ubuf;
compat_ulong_t reg;
- if (!kbuf && !user_read_access_begin(u, count))
+ if (!user_read_access_begin(u, count))
return -EFAULT;
pos /= sizeof(reg);
count /= sizeof(reg);
- if (kbuf)
- for (; count > 0 && pos < PT_MSR; --count)
- regs[pos++] = *k++;
- else
- for (; count > 0 && pos < PT_MSR; --count) {
- unsafe_get_user(reg, u++, Efault);
- regs[pos++] = reg;
- }
-
+ for (; count > 0 && pos < PT_MSR; --count) {
+ unsafe_get_user(reg, u++, Efault);
+ regs[pos++] = reg;
+ }
if (count > 0 && pos == PT_MSR) {
- if (kbuf)
- reg = *k++;
- else
- unsafe_get_user(reg, u++, Efault);
+ unsafe_get_user(reg, u++, Efault);
set_user_msr(target, reg);
++pos;
--count;
}
- if (kbuf) {
- for (; count > 0 && pos <= PT_MAX_PUT_REG; --count)
- regs[pos++] = *k++;
- for (; count > 0 && pos < PT_TRAP; --count, ++pos)
- ++k;
- } else {
- for (; count > 0 && pos <= PT_MAX_PUT_REG; --count) {
- unsafe_get_user(reg, u++, Efault);
- regs[pos++] = reg;
- }
- for (; count > 0 && pos < PT_TRAP; --count, ++pos)
- unsafe_get_user(reg, u++, Efault);
+ for (; count > 0 && pos <= PT_MAX_PUT_REG; --count) {
+ unsafe_get_user(reg, u++, Efault);
+ regs[pos++] = reg;
}
+ for (; count > 0 && pos < PT_TRAP; --count, ++pos)
+ unsafe_get_user(reg, u++, Efault);
if (count > 0 && pos == PT_TRAP) {
- if (kbuf)
- reg = *k++;
- else
- unsafe_get_user(reg, u++, Efault);
+ unsafe_get_user(reg, u++, Efault);
set_user_trap(target, reg);
++pos;
--count;
}
- if (!kbuf)
- user_read_access_end();
+ user_read_access_end();
- kbuf = k;
ubuf = u;
pos *= sizeof(reg);
count *= sizeof(reg);
- user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+ user_regset_copyin_ignore(&pos, &count, NULL, &ubuf,
(PT_TRAP + 1) * sizeof(reg), -1);
return 0;
@@ -791,6 +807,18 @@ int gpr32_set_common(struct task_struct *target,
return -EFAULT;
}
+int gpr32_set_common(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf,
+ unsigned long *regs)
+{
+ if (kbuf)
+ return gpr32_set_common_kernel(target, regset, pos, count, kbuf, regs);
+ else
+ return gpr32_set_common_user(target, regset, pos, count, ubuf, regs);
+}
+
static int gpr32_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
--
2.40.1
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