diff options
Diffstat (limited to 'recipes-kernel/linux/linux-qoriq/powerpc-vdso64-Use-double-word-compare-on-pointers.patch')
| -rw-r--r-- | recipes-kernel/linux/linux-qoriq/powerpc-vdso64-Use-double-word-compare-on-pointers.patch | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/recipes-kernel/linux/linux-qoriq/powerpc-vdso64-Use-double-word-compare-on-pointers.patch b/recipes-kernel/linux/linux-qoriq/powerpc-vdso64-Use-double-word-compare-on-pointers.patch new file mode 100644 index 00000000..9fa40de4 --- /dev/null +++ b/recipes-kernel/linux/linux-qoriq/powerpc-vdso64-Use-double-word-compare-on-pointers.patch @@ -0,0 +1,67 @@ +From 5045ea37377ce8cca6890d32b127ad6770e6dce5 Mon Sep 17 00:00:00 2001 +From: Anton Blanchard <anton@samba.org> +Date: Sun, 25 Sep 2016 17:16:53 +1000 +Subject: [PATCH] powerpc/vdso64: Use double word compare on pointers + +__kernel_get_syscall_map() and __kernel_clock_getres() use cmpli to +check if the passed in pointer is non zero. cmpli maps to a 32 bit +compare on binutils, so we ignore the top 32 bits. + +A simple test case can be created by passing in a bogus pointer with +the bottom 32 bits clear. Using a clk_id that is handled by the VDSO, +then one that is handled by the kernel shows the problem: + + printf("%d\n", clock_getres(CLOCK_REALTIME, (void *)0x100000000)); + printf("%d\n", clock_getres(CLOCK_BOOTTIME, (void *)0x100000000)); + +And we get: + + 0 + -1 + +The bigger issue is if we pass a valid pointer with the bottom 32 bits +clear, in this case we will return success but won't write any data +to the pointer. + +I stumbled across this issue because the LLVM integrated assembler +doesn't accept cmpli with 3 arguments. Fix this by converting them to +cmpldi. + +Fixes: a7f290dad32e ("[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel") +Cc: stable@vger.kernel.org # v2.6.15+ +Signed-off-by: Anton Blanchard <anton@samba.org> +Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> +--- + arch/powerpc/kernel/vdso64/datapage.S | 2 +- + arch/powerpc/kernel/vdso64/gettimeofday.S | 2 +- + 2 files changed, 2 insertions(+), 2 deletions(-) + +diff --git a/arch/powerpc/kernel/vdso64/datapage.S b/arch/powerpc/kernel/vdso64/datapage.S +index 184a6ba..abf17fe 100644 +--- a/arch/powerpc/kernel/vdso64/datapage.S ++++ b/arch/powerpc/kernel/vdso64/datapage.S +@@ -59,7 +59,7 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map) + bl V_LOCAL_FUNC(__get_datapage) + mtlr r12 + addi r3,r3,CFG_SYSCALL_MAP64 +- cmpli cr0,r4,0 ++ cmpldi cr0,r4,0 + crclr cr0*4+so + beqlr + li r0,NR_syscalls +diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S +index a76b4af..3820213 100644 +--- a/arch/powerpc/kernel/vdso64/gettimeofday.S ++++ b/arch/powerpc/kernel/vdso64/gettimeofday.S +@@ -145,7 +145,7 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) + bne cr0,99f + + li r3,0 +- cmpli cr0,r4,0 ++ cmpldi cr0,r4,0 + crclr cr0*4+so + beqlr + lis r5,CLOCK_REALTIME_RES@h +-- +2.7.4 + |