On 20 October 2017 at 09:24, Ingo Molnar <mingo@xxxxxxxxxx> wrote: > > * Thomas Garnier <thgarnie@xxxxxxxxxx> wrote: > >> Change the assembly code to use only relative references of symbols for the >> kernel to be PIE compatible. >> >> Position Independent Executable (PIE) support will allow to extended the >> KASLR randomization range below the -2G memory limit. > >> diff --git a/arch/x86/crypto/aes-x86_64-asm_64.S b/arch/x86/crypto/aes-x86_64-asm_64.S >> index 8739cf7795de..86fa068e5e81 100644 >> --- a/arch/x86/crypto/aes-x86_64-asm_64.S >> +++ b/arch/x86/crypto/aes-x86_64-asm_64.S >> @@ -48,8 +48,12 @@ >> #define R10 %r10 >> #define R11 %r11 >> >> +/* Hold global for PIE suport */ >> +#define RBASE %r12 >> + >> #define prologue(FUNC,KEY,B128,B192,r1,r2,r5,r6,r7,r8,r9,r10,r11) \ >> ENTRY(FUNC); \ >> + pushq RBASE; \ >> movq r1,r2; \ >> leaq KEY+48(r8),r9; \ >> movq r10,r11; \ >> @@ -74,54 +78,63 @@ >> movl r6 ## E,4(r9); \ >> movl r7 ## E,8(r9); \ >> movl r8 ## E,12(r9); \ >> + popq RBASE; \ >> ret; \ >> ENDPROC(FUNC); >> >> +#define round_mov(tab_off, reg_i, reg_o) \ >> + leaq tab_off(%rip), RBASE; \ >> + movl (RBASE,reg_i,4), reg_o; >> + >> +#define round_xor(tab_off, reg_i, reg_o) \ >> + leaq tab_off(%rip), RBASE; \ >> + xorl (RBASE,reg_i,4), reg_o; >> + >> #define round(TAB,OFFSET,r1,r2,r3,r4,r5,r6,r7,r8,ra,rb,rc,rd) \ >> movzbl r2 ## H,r5 ## E; \ >> movzbl r2 ## L,r6 ## E; \ >> - movl TAB+1024(,r5,4),r5 ## E;\ >> + round_mov(TAB+1024, r5, r5 ## E)\ >> movw r4 ## X,r2 ## X; \ >> - movl TAB(,r6,4),r6 ## E; \ >> + round_mov(TAB, r6, r6 ## E) \ >> roll $16,r2 ## E; \ >> shrl $16,r4 ## E; \ >> movzbl r4 ## L,r7 ## E; \ >> movzbl r4 ## H,r4 ## E; \ >> xorl OFFSET(r8),ra ## E; \ >> xorl OFFSET+4(r8),rb ## E; \ >> - xorl TAB+3072(,r4,4),r5 ## E;\ >> - xorl TAB+2048(,r7,4),r6 ## E;\ >> + round_xor(TAB+3072, r4, r5 ## E)\ >> + round_xor(TAB+2048, r7, r6 ## E)\ >> movzbl r1 ## L,r7 ## E; \ >> movzbl r1 ## H,r4 ## E; \ >> - movl TAB+1024(,r4,4),r4 ## E;\ >> + round_mov(TAB+1024, r4, r4 ## E)\ >> movw r3 ## X,r1 ## X; \ >> roll $16,r1 ## E; \ >> shrl $16,r3 ## E; \ >> - xorl TAB(,r7,4),r5 ## E; \ >> + round_xor(TAB, r7, r5 ## E) \ >> movzbl r3 ## L,r7 ## E; \ >> movzbl r3 ## H,r3 ## E; \ >> - xorl TAB+3072(,r3,4),r4 ## E;\ >> - xorl TAB+2048(,r7,4),r5 ## E;\ >> + round_xor(TAB+3072, r3, r4 ## E)\ >> + round_xor(TAB+2048, r7, r5 ## E)\ >> movzbl r1 ## L,r7 ## E; \ >> movzbl r1 ## H,r3 ## E; \ >> shrl $16,r1 ## E; \ >> - xorl TAB+3072(,r3,4),r6 ## E;\ >> - movl TAB+2048(,r7,4),r3 ## E;\ >> + round_xor(TAB+3072, r3, r6 ## E)\ >> + round_mov(TAB+2048, r7, r3 ## E)\ >> movzbl r1 ## L,r7 ## E; \ >> movzbl r1 ## H,r1 ## E; \ >> - xorl TAB+1024(,r1,4),r6 ## E;\ >> - xorl TAB(,r7,4),r3 ## E; \ >> + round_xor(TAB+1024, r1, r6 ## E)\ >> + round_xor(TAB, r7, r3 ## E) \ >> movzbl r2 ## H,r1 ## E; \ >> movzbl r2 ## L,r7 ## E; \ >> shrl $16,r2 ## E; \ >> - xorl TAB+3072(,r1,4),r3 ## E;\ >> - xorl TAB+2048(,r7,4),r4 ## E;\ >> + round_xor(TAB+3072, r1, r3 ## E)\ >> + round_xor(TAB+2048, r7, r4 ## E)\ >> movzbl r2 ## H,r1 ## E; \ >> movzbl r2 ## L,r2 ## E; \ >> xorl OFFSET+8(r8),rc ## E; \ >> xorl OFFSET+12(r8),rd ## E; \ >> - xorl TAB+1024(,r1,4),r3 ## E;\ >> - xorl TAB(,r2,4),r4 ## E; >> + round_xor(TAB+1024, r1, r3 ## E)\ >> + round_xor(TAB, r2, r4 ## E) > > This appears to be adding unconditional overhead to a function that was moved to > assembly to improve its performance. > I did some benchmarking on this code a while ago and, interestingly, it was slower than the generic C implementation (on a Pentium E2200), so we may want to consider whether we still need this driver in the first place. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization