4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tom Lendacky thomas.lendacky@amd.com
commit 1303880179e67c59e801429b7e5d0f6b21137d99 upstream.
Clean up the use of PUSH and POP and when registers are saved in the __enc_copy() assembly function in order to improve the readability of the code.
Move parameter register saving into general purpose registers earlier in the code and move all the pushes to the beginning of the function with corresponding pops at the end.
We do this to prepare fixes.
Tested-by: Gabriel Craciunescu nix.or.die@gmail.com Signed-off-by: Tom Lendacky thomas.lendacky@amd.com Reviewed-by: Borislav Petkov bp@suse.de Cc: Borislav Petkov bp@alien8.de Cc: Brijesh Singh brijesh.singh@amd.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/20180110192556.6026.74187.stgit@tlendack-t1.amdoffi... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/mm/mem_encrypt_boot.S | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
--- a/arch/x86/mm/mem_encrypt_boot.S +++ b/arch/x86/mm/mem_encrypt_boot.S @@ -103,20 +103,19 @@ ENTRY(__enc_copy) orq $X86_CR4_PGE, %rdx mov %rdx, %cr4
+ push %r15 + + movq %rcx, %r9 /* Save kernel length */ + movq %rdi, %r10 /* Save encrypted kernel address */ + movq %rsi, %r11 /* Save decrypted kernel address */ + /* Set the PAT register PA5 entry to write-protect */ - push %rcx movl $MSR_IA32_CR_PAT, %ecx rdmsr - push %rdx /* Save original PAT value */ + mov %rdx, %r15 /* Save original PAT value */ andl $0xffff00ff, %edx /* Clear PA5 */ orl $0x00000500, %edx /* Set PA5 to WP */ wrmsr - pop %rdx /* RDX contains original PAT value */ - pop %rcx - - movq %rcx, %r9 /* Save kernel length */ - movq %rdi, %r10 /* Save encrypted kernel address */ - movq %rsi, %r11 /* Save decrypted kernel address */
wbinvd /* Invalidate any cache entries */
@@ -138,12 +137,13 @@ ENTRY(__enc_copy) jnz 1b /* Kernel length not zero? */
/* Restore PAT register */ - push %rdx /* Save original PAT value */ movl $MSR_IA32_CR_PAT, %ecx rdmsr - pop %rdx /* Restore original PAT value */ + mov %r15, %rdx /* Restore original PAT value */ wrmsr
+ pop %r15 + ret .L__enc_copy_end: ENDPROC(__enc_copy)