From 9cb81a170fcddbc342804cb8e42eb9fe50d1afc5 Mon Sep 17 00:00:00 2001 From: Jonathan Wright Date: Mon, 28 Sep 2020 13:35:51 +0100 Subject: [PATCH] aarch64: Add Armv8.5-A BTI support Add Branch Target Identifiers (BTIs) to all functions defined in AArch64 assembly files. Most of the BTI landing pads are added automatically by the 'function' macro. BTI support is turned on or off at compile time based on the presence of the __ARM_FEATURE_BTI_DEFAULT feature macro. A binary compiled with BTI support can be executed on an Armv8-A processor without BTI support because the instructions are defined in NOP space. Signed-off-by: Jonathan Wright Signed-off-by: Elijah Ahmad Change-Id: I94182ac3059dece5152203b717633f6dbcb9c0ac --- libavcodec/aarch64/fft_neon.S | 4 ++++ libavcodec/aarch64/h264idct_neon.S | 4 ++++ libavutil/aarch64/asm.S | 30 ++++++++++++++++++++++++++++++ 3 files changed, 38 insertions(+) diff --git a/libavcodec/aarch64/fft_neon.S b/libavcodec/aarch64/fft_neon.S index 862039f97d..b4020fc8c7 100644 --- a/libavcodec/aarch64/fft_neon.S +++ b/libavcodec/aarch64/fft_neon.S @@ -36,6 +36,7 @@ function fft4_neon + AARCH64_VALID_JUMP_TARGET ld1 {v0.2s,v1.2s,v2.2s,v3.2s}, [x0] fadd v4.2s, v0.2s, v1.2s // r0+r1,i0+i1 @@ -58,6 +59,7 @@ function fft4_neon endfunc function fft8_neon + AARCH64_VALID_JUMP_TARGET mov x1, x0 ld1 {v0.2s, v1.2s, v2.2s, v3.2s}, [x0], #32 ld1 {v16.2s,v17.2s,v18.2s,v19.2s}, [x0] @@ -108,6 +110,7 @@ function fft8_neon endfunc function fft16_neon + AARCH64_VALID_JUMP_TARGET mov x1, x0 ld1 {v0.2s, v1.2s, v2.2s, v3.2s}, [x0], #32 ld1 {v16.2s,v17.2s,v18.2s,v19.2s}, [x0], #32 @@ -337,6 +340,7 @@ endfunc .macro def_fft n, n2, n4 function fft\n\()_neon, align=6 + AARCH64_VALID_JUMP_TARGET sub sp, sp, #16 stp x28, x30, [sp] add x28, x0, #\n4*2*8 diff --git a/libavcodec/aarch64/h264idct_neon.S b/libavcodec/aarch64/h264idct_neon.S index 7de44205d3..7d2879b0ce 100644 --- a/libavcodec/aarch64/h264idct_neon.S +++ b/libavcodec/aarch64/h264idct_neon.S @@ -24,6 +24,7 @@ function ff_h264_idct_add_neon, export=1 .L_ff_h264_idct_add_neon: + AARCH64_VALID_CALL_TARGET ld1 {v0.4H, v1.4H, v2.4H, v3.4H}, [x1] sxtw x2, w2 movi v30.8H, #0 @@ -79,6 +80,7 @@ endfunc function ff_h264_idct_dc_add_neon, export=1 .L_ff_h264_idct_dc_add_neon: + AARCH64_VALID_CALL_TARGET sxtw x2, w2 mov w3, #0 ld1r {v2.8H}, [x1] @@ -266,6 +268,7 @@ endfunc function ff_h264_idct8_add_neon, export=1 .L_ff_h264_idct8_add_neon: + AARCH64_VALID_CALL_TARGET movi v19.8H, #0 sxtw x2, w2 ld1 {v24.8H, v25.8H}, [x1] @@ -330,6 +333,7 @@ endfunc function ff_h264_idct8_dc_add_neon, export=1 .L_ff_h264_idct8_dc_add_neon: + AARCH64_VALID_CALL_TARGET mov w3, #0 sxtw x2, w2 ld1r {v31.8H}, [x1] diff --git a/libavutil/aarch64/asm.S b/libavutil/aarch64/asm.S index d1fa72b3c6..f78942eb86 100644 --- a/libavutil/aarch64/asm.S +++ b/libavutil/aarch64/asm.S @@ -36,6 +36,35 @@ # define __has_feature(x) 0 #endif +/* Support macros for the Armv8.5-A Branch Target Identification feature which + * requires emitting a .note.gnu.property section with the appropriate + * architecture-dependent feature bits set. + * Read more: "ELF for the Arm® 64-bit Architecture" + */ +#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1) +# define GNU_PROPERTY_AARCH64_BTI (1 << 0) // Has BTI +# define AARCH64_VALID_CALL_TARGET hint #34 // BTI 'c' +# define AARCH64_VALID_JUMP_TARGET hint #38 // BTI 'j' +#else +# define GNU_PROPERTY_AARCH64_BTI 0 // No BTI +# define AARCH64_VALID_CALL_TARGET +# define AARCH64_VALID_JUMP_TARGET +#endif + +#if (GNU_PROPERTY_AARCH64_BTI != 0) + .pushsection .note.gnu.property, "a"; + .balign 8; + .long 4; + .long 0x10; + .long 0x5; + .asciz "GNU"; + .long 0xc0000000; /* GNU_PROPERTY_AARCH64_FEATURE_1_AND */ + .long 4; + .long GNU_PROPERTY_AARCH64_BTI; + .long 0 + .popsection +#endif + .macro function name, export=0, align=2 .macro endfunc ELF .size \name, . - \name @@ -49,6 +78,7 @@ FUNC .endfunc ELF .type EXTERN_ASM\name, %function FUNC .func EXTERN_ASM\name EXTERN_ASM\name: + AARCH64_VALID_CALL_TARGET .else ELF .type \name, %function FUNC .func \name -- 2.30.1 (Apple Git-130)