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powerpc/ptrace: Split gpr32_set_common

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objtool reports the following warning:

  arch/powerpc/kernel/ptrace/ptrace-view.o: warning: objtool:
    gpr32_set_common+0x23c (.text+0x860): redundant UACCESS disable

gpr32_set_common() conditionally opens and closes UACCESS based on
whether kbuf pointer 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@csgroup.eu>
[mpe: Fix oops in gpr32_set_common_user() due to NULL kbuf]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b8d6ae4483fcfd17524e79d803c969694a85cc02.1687428075.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy
2023-06-22 12:01:23 +02:00
committed by Michael Ellerman
parent 0e216fa576
commit 9a32584bc1
1 changed files with 67 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/powerpc/kernel/ptrace/ptrace-view.c
+67 -38
View File
@@ -716,69 +716,86 @@ 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;
const void *kbuf = NULL;
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);
@@ -791,6 +808,18 @@ Efault:
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)