@@ -372,9 +372,32 @@ int patch_instruction(u32 *addr, ppc_inst_t instr)
}
NOKPROBE_SYMBOL(patch_instruction);
+static int patch_memset64(u64 *addr, u64 val, size_t count)
+{
+ for (u64 *end = addr + count; addr < end; addr++)
+ __put_kernel_nofault(addr, &val, u64, failed);
+
+ return 0;
+
+failed:
+ return -EPERM;
+}
+
+static int patch_memset32(u32 *addr, u32 val, size_t count)
+{
+ for (u32 *end = addr + count; addr < end; addr++)
+ __put_kernel_nofault(addr, &val, u32, failed);
+
+ return 0;
+
+failed:
+ return -EPERM;
+}
+
static int __patch_instructions(u32 *patch_addr, u32 *code, size_t len, bool repeat_instr)
{
unsigned long start = (unsigned long)patch_addr;
+ int err;
/* Repeat instruction */
if (repeat_instr) {
@@ -383,19 +406,19 @@ static int __patch_instructions(u32 *patch_addr, u32 *code, size_t len, bool rep
if (ppc_inst_prefixed(instr)) {
u64 val = ppc_inst_as_ulong(instr);
- memset64((u64 *)patch_addr, val, len / 8);
+ err = patch_memset64((u64 *)patch_addr, val, len / 8);
} else {
u32 val = ppc_inst_val(instr);
- memset32(patch_addr, val, len / 4);
+ err = patch_memset32(patch_addr, val, len / 4);
}
} else {
- memcpy(patch_addr, code, len);
+ err = copy_to_kernel_nofault(patch_addr, code, len);
}
smp_wmb(); /* smp write barrier */
flush_icache_range(start, start + len);
- return 0;
+ return err;
}
/*
The patching page set up as a writable alias may be in quadrant 0 (userspace) if the temporary mm path is used. This causes sanitiser failures if so. Sanitiser failures also occur on the non-mm path because the plain memset family is instrumented, and KASAN treats the patching window as poisoned. Introduce locally defined patch_* variants of memset that perform an uninstrumented lower level set, as well as detecting write errors like the original single patch variant does. copy_to_user() is not correct here, as the PTE makes it a proper kernel page (the EAA is privileged access only, RW). It just happens to be in quadrant 0 because that's the hardware's mechanism for using the current PID vs PID 0 in translations. Importantly, it's incorrect to allow user page accesses. Now that the patching memsets are used, we also propagate a failure up to the caller as the single patch variant does. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> --- v2: * Fix typo in EAA (from EEA) * Fix references to quadrant number (0, not 1) * Use copy_to_kernel_nofault() over custom memcpy * Drop custom memcpy optimisation patch --- arch/powerpc/lib/code-patching.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-)