| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 083/266] powerpc/fsl: Sanitize the syscall table for NXP PowerPC 32 bit platforms | Date | Wed, 15 May 2019 12:53:10 +0200 |
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From: Diana Craciun <diana.craciun@nxp.com>
commit c28218d4abbf4f2035495334d8bfcba64bda4787 upstream.
Used barrier_nospec to sanitize the syscall table.
Signed-off-by: Diana Craciun <diana.craciun@nxp.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/powerpc/kernel/entry_32.S | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -33,6 +33,7 @@ #include <asm/unistd.h> #include <asm/ftrace.h> #include <asm/ptrace.h> +#include <asm/barrier.h> /* * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE. @@ -340,6 +341,15 @@ syscall_dotrace_cont: ori r10,r10,sys_call_table@l slwi r0,r0,2 bge- 66f + + barrier_nospec_asm + /* + * Prevent the load of the handler below (based on the user-passed + * system call number) being speculatively executed until the test + * against NR_syscalls and branch to .66f above has + * committed. + */ + lwzx r10,r10,r0 /* Fetch system call handler [ptr] */ mtlr r10 addi r9,r1,STACK_FRAME_OVERHEAD
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