4.14-stable review patch. If anyone has any objections, please let me know.
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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/ptrace.h> #include <asm/export.h> +#include <asm/barrier.h>
/* * MSR_KERNEL is > 0x10000 on 4xx/Book-E since it include MSR_CE. @@ -358,6 +359,15 @@ 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