projects / platform / upstream / libffi.git / commitdiff
? search:
summary | shortlog | log | commit | commitdiff | tree
raw | patch | inline | side by side (parent: 11af219)
aarch64: Write the BTI instructions as "hint" instructions (#810)
authorMartin Storsjö <martin@martin.st>
Tue, 28 Nov 2023 22:38:13 +0000 (00:38 +0200)
committerGitHub <noreply@github.com>
Tue, 28 Nov 2023 22:38:13 +0000 (17:38 -0500)
GNU binutils refuses to assemble the direct BTI instructions unless
the target architecture explicitly supports BTI, ending up with errors
such as

    ../src/aarch64/sysv.S: Assembler messages:
    ../src/aarch64/sysv.S:87: Error: selected processor does not support `bti c'
    ../src/aarch64/sysv.S:156: Error: selected processor does not support `bti j'

Building with -march=armv8.5-a fixes building this.

However, the BTI instructions assemble into hint instructions, that
are ignored by processors that don't implement them. Therefore it is
possible to assemble them for the baseline armv8.0-a target as well,
by replacing "bti j" with "hint #36", "bti c" with "hint #34" and
"bti jc" with "hint #38"; this assembles into the same instruction
bits.

src/aarch64/ffi.c patch | blob | history
src/aarch64/sysv.S patch | blob | history

diff --git a/src/aarch64/ffi.c b/src/aarch64/ffi.c
index 67b18fbfb71d333faef0c2f4843e747445b5e106..8661a352b7cb31459fa2bb6ad049d6d44f9a744b 100644 (file)
--- a/src/aarch64/ffi.c
+++ b/src/aarch64/ffi.c
@@ -386,55 +386,56 @@ extend_hfa_type (void *dest, void *src, int h)
   ssize_t f = h - AARCH64_RET_S4;
   void *x0;
 
+#define BTI_J "hint #36"
   asm volatile (
        "adr    %0, 0f\n"
 "      add     %0, %0, %1\n"
 "      br      %0\n"
-"0:    bti     j\n"                    /* S4 */
+"0:    "BTI_J"\n"                      /* S4 */
 "      ldp     s16, s17, [%3]\n"
 "      ldp     s18, s19, [%3, #8]\n"
 "      b       4f\n"
-"      bti     j\n"                    /* S3 */
+"      "BTI_J"\n"                      /* S3 */
 "      ldp     s16, s17, [%3]\n"
 "      ldr     s18, [%3, #8]\n"
 "      b       3f\n"
-"      bti     j\n"                    /* S2 */
+"      "BTI_J"\n"                      /* S2 */
 "      ldp     s16, s17, [%3]\n"
 "      b       2f\n"
 "      nop\n"
-"      bti     j\n"                    /* S1 */
+"      "BTI_J"\n"                      /* S1 */
 "      ldr     s16, [%3]\n"
 "      b       1f\n"
 "      nop\n"
-"      bti     j\n"                    /* D4 */
+"      "BTI_J"\n"                      /* D4 */
 "      ldp     d16, d17, [%3]\n"
 "      ldp     d18, d19, [%3, #16]\n"
 "      b       4f\n"
-"      bti     j\n"                    /* D3 */
+"      "BTI_J"\n"                      /* D3 */
 "      ldp     d16, d17, [%3]\n"
 "      ldr     d18, [%3, #16]\n"
 "      b       3f\n"
-"      bti     j\n"                    /* D2 */
+"      "BTI_J"\n"                      /* D2 */
 "      ldp     d16, d17, [%3]\n"
 "      b       2f\n"
 "      nop\n"
-"      bti     j\n"                    /* D1 */
+"      "BTI_J"\n"                      /* D1 */
 "      ldr     d16, [%3]\n"
 "      b       1f\n"
 "      nop\n"
-"      bti     j\n"                    /* Q4 */
+"      "BTI_J"\n"                      /* Q4 */
 "      ldp     q16, q17, [%3]\n"
 "      ldp     q18, q19, [%3, #32]\n"
 "      b       4f\n"
-"      bti     j\n"                    /* Q3 */
+"      "BTI_J"\n"                      /* Q3 */
 "      ldp     q16, q17, [%3]\n"
 "      ldr     q18, [%3, #32]\n"
 "      b       3f\n"
-"      bti     j\n"                    /* Q2 */
+"      "BTI_J"\n"                      /* Q2 */
 "      ldp     q16, q17, [%3]\n"
 "      b       2f\n"
 "      nop\n"
-"      bti     j\n"                    /* Q1 */
+"      "BTI_J"\n"                      /* Q1 */
 "      ldr     q16, [%3]\n"
 "      b       1f\n"
 "4:    str     q19, [%2, #48]\n"
diff --git a/src/aarch64/sysv.S b/src/aarch64/sysv.S
index 9f4188e00faca0b4b62894e379c03d09e8ac0aa3..90816752d480c63a03303f15ee8b9c91ec569626 100644 (file)
--- a/src/aarch64/sysv.S
+++ b/src/aarch64/sysv.S
@@ -64,6 +64,9 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #define PTR_SIZE       8
 #endif
 
+#define BTI_C hint #34
+#define BTI_J hint #36
+
        .text
        .align 4
 
@@ -84,7 +87,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 
        cfi_startproc
 CNAME(ffi_call_SYSV):
-       bti     c
+       BTI_C
        /* Sign the lr with x1 since that is where it will be stored */
        SIGN_LR_WITH_REG(x1)
 
@@ -153,15 +156,15 @@ CNAME(ffi_call_SYSV):
           and therefore we want to extend to 64 bits; these types
           have two consecutive entries allocated for them.  */
        .align  4
-0:     bti     j                       /* VOID */
+0:     BTI_J                           /* VOID */
        b 99f
        nop 
        nop
-1:     bti     j                       /* INT64 */
+1:     BTI_J                           /* INT64 */
        str     x0, [x3]
        b 99f
        nop
-2:     bti     j                       /* INT128 */
+2:     BTI_J                           /* INT128 */
        stp     x0, x1, [x3]
        b 99f
        nop
@@ -185,55 +188,55 @@ CNAME(ffi_call_SYSV):
        b 99f
        nop
        nop
-8:     bti     j                       /* S4 */
+8:     BTI_J                           /* S4 */
        st4     { v0.s, v1.s, v2.s, v3.s }[0], [x3]
        b 99f
        nop
-9:     bti     j                       /* S3 */
+9:     BTI_J                           /* S3 */
        st3     { v0.s, v1.s, v2.s }[0], [x3]
        b 99f
        nop
-10:    bti     j                       /* S2 */
+10:    BTI_J                           /* S2 */
        stp     s0, s1, [x3]
        b 99f
        nop
-11:    bti     j
+11:    BTI_J
        str     s0, [x3]                /* S1 */
        b 99f
        nop
-12:    bti     j                       /* D4 */
+12:    BTI_J                           /* D4 */
        st4     { v0.d, v1.d, v2.d, v3.d }[0], [x3]
        b 99f
        nop
-13:    bti     j                       /* D3 */
+13:    BTI_J                           /* D3 */
        st3     { v0.d, v1.d, v2.d }[0], [x3]
        b 99f
        nop
-14:    bti     j                       /* D2 */
+14:    BTI_J                           /* D2 */
        stp     d0, d1, [x3]
        b 99f
        nop
-15:    bti     j                       /* D1 */
+15:    BTI_J                           /* D1 */
        str     d0, [x3]
        b 99f
        nop
-16:    bti     j                       /* Q4 */
+16:    BTI_J                           /* Q4 */
        str     q3, [x3, #48]
        nop
        nop
-17:    bti     j                       /* Q3 */
+17:    BTI_J                           /* Q3 */
        str     q2, [x3, #32]
        nop
        nop
-18:    bti     j                       /* Q2 */
+18:    BTI_J                           /* Q2 */
        stp     q0, q1, [x3]
        b 99f
        nop
-19:    bti     j                       /* Q1 */
+19:    BTI_J                           /* Q1 */
        str     q0, [x3]
        b 99f
        nop
-20:    bti     j                       /* UINT8 */
+20:    BTI_J                           /* UINT8 */
        uxtb    w0, w0
        str     x0, [x3]
        nop
@@ -241,7 +244,7 @@ CNAME(ffi_call_SYSV):
        nop
        nop
        nop
-22:    bti     j                       /* UINT16 */
+22:    BTI_J                           /* UINT16 */
        uxth    w0, w0
        str     x0, [x3]
        nop
@@ -249,7 +252,7 @@ CNAME(ffi_call_SYSV):
        nop
        nop
        nop
-24:    bti     j                       /* UINT32 */
+24:    BTI_J                           /* UINT32 */
        mov     w0, w0
        str     x0, [x3]
        nop
@@ -257,7 +260,7 @@ CNAME(ffi_call_SYSV):
        nop
        nop
        nop
-26:    bti     j                       /* SINT8 */
+26:    BTI_J                           /* SINT8 */
        sxtb    x0, w0
        str     x0, [x3]
        nop
@@ -265,7 +268,7 @@ CNAME(ffi_call_SYSV):
        nop
        nop
        nop
-28:    bti     j                       /* SINT16 */
+28:    BTI_J                           /* SINT16 */
        sxth    x0, w0
        str     x0, [x3]
        nop
@@ -273,7 +276,7 @@ CNAME(ffi_call_SYSV):
        nop
        nop
        nop
-30:    bti     j                       /* SINT32 */
+30:    BTI_J                           /* SINT32 */
        sxtw    x0, w0
        str     x0, [x3]
        nop
@@ -317,7 +320,7 @@ CNAME(ffi_call_SYSV):
        .align 4
 CNAME(ffi_closure_SYSV_V):
        cfi_startproc
-       bti     c
+       BTI_C
        SIGN_LR
        stp     x29, x30, [sp, #-ffi_closure_SYSV_FS]!
        cfi_adjust_cfa_offset (ffi_closure_SYSV_FS)
@@ -342,7 +345,7 @@ CNAME(ffi_closure_SYSV_V):
        .align  4
        cfi_startproc
 CNAME(ffi_closure_SYSV):
-       bti     c
+       BTI_C
        SIGN_LR
        stp     x29, x30, [sp, #-ffi_closure_SYSV_FS]!
        cfi_adjust_cfa_offset (ffi_closure_SYSV_FS)
@@ -378,15 +381,15 @@ L(do_closure):
 
        /* Note that each table entry is 4 insns, and thus 16 bytes.  */
        .align  4
-0:     bti     j                       /* VOID */
+0:     BTI_J                           /* VOID */
        b       99f
        nop
        nop
-1:     bti     j                       /* INT64 */
+1:     BTI_J                           /* INT64 */
        ldr     x0, [x3]
        b       99f
        nop
-2:     bti     j                       /* INT128 */
+2:     BTI_J                           /* INT128 */
        ldp     x0, x1, [x3]
        b       99f
        nop
@@ -410,55 +413,55 @@ L(do_closure):
        nop
        nop
        nop
-8:     bti     j                       /* S4 */
+8:     BTI_J                           /* S4 */
        ldr     s3, [x3, #12]
        nop
        nop
-9:     bti     j                       /* S3 */
+9:     BTI_J                           /* S3 */
        ldr     s2, [x3, #8]
        nop
        nop
-10:    bti     j                       /* S2 */
+10:    BTI_J                           /* S2 */
        ldp     s0, s1, [x3]
        b       99f
        nop
-11:    bti     j                       /* S1 */
+11:    BTI_J                           /* S1 */
        ldr     s0, [x3]
        b       99f
        nop
-12:    bti     j                       /* D4 */
+12:    BTI_J                           /* D4 */
        ldr     d3, [x3, #24]
        nop
        nop
-13:    bti     j                       /* D3 */
+13:    BTI_J                           /* D3 */
        ldr     d2, [x3, #16]
        nop
        nop
-14:    bti     j                       /* D2 */
+14:    BTI_J                           /* D2 */
        ldp     d0, d1, [x3]
        b       99f
        nop
-15:    bti     j                       /* D1 */
+15:    BTI_J                           /* D1 */
        ldr     d0, [x3]
        b       99f
        nop
-16:    bti     j                       /* Q4 */
+16:    BTI_J                           /* Q4 */
        ldr     q3, [x3, #48]
        nop
        nop
-17:    bti     j                       /* Q3 */
+17:    BTI_J                           /* Q3 */
        ldr     q2, [x3, #32]
        nop
        nop
-18:    bti     j                       /* Q2 */
+18:    BTI_J                           /* Q2 */
        ldp     q0, q1, [x3]
        b       99f
        nop
-19:    bti     j                       /* Q1 */
+19:    BTI_J                           /* Q1 */
        ldr     q0, [x3]
        b       99f
        nop
-20:    bti     j                       /* UINT8 */
+20:    BTI_J                           /* UINT8 */
        ldrb    w0, [x3, #BE(7)]
        b       99f
        nop
@@ -466,7 +469,7 @@ L(do_closure):
        nop
        nop
        nop
-22:    bti     j                       /* UINT16 */
+22:    BTI_J                           /* UINT16 */
        ldrh    w0, [x3, #BE(6)]
        b       99f
        nop
@@ -474,7 +477,7 @@ L(do_closure):
        nop
        nop
        nop
-24:    bti     j                       /* UINT32 */
+24:    BTI_J                           /* UINT32 */
        ldr     w0, [x3, #BE(4)]
        b       99f
        nop
@@ -482,7 +485,7 @@ L(do_closure):
        nop
        nop
        nop
-26:    bti     j                       /* SINT8 */
+26:    BTI_J                           /* SINT8 */
        ldrsb   x0, [x3, #BE(7)]
        b       99f
        nop
@@ -490,7 +493,7 @@ L(do_closure):
        nop
        nop
        nop
-28:    bti     j                       /* SINT16 */
+28:    BTI_J                           /* SINT16 */
        ldrsh   x0, [x3, #BE(6)]
        b       99f
        nop
@@ -498,7 +501,7 @@ L(do_closure):
        nop
        nop
        nop
-30:    bti     j                       /* SINT32 */
+30:    BTI_J                           /* SINT32 */
        ldrsw   x0, [x3, #BE(4)]
        nop
        nop
@@ -614,7 +617,7 @@ CNAME(ffi_closure_trampoline_table_page):
        .align 4
 CNAME(ffi_go_closure_SYSV_V):
        cfi_startproc
-       bti     c
+       BTI_C
        stp     x29, x30, [sp, #-ffi_closure_SYSV_FS]!
        cfi_adjust_cfa_offset (ffi_closure_SYSV_FS)
        cfi_rel_offset (x29, 0)
@@ -638,7 +641,7 @@ CNAME(ffi_go_closure_SYSV_V):
        .align  4
        cfi_startproc
 CNAME(ffi_go_closure_SYSV):
-       bti     c
+       BTI_C
        stp     x29, x30, [sp, #-ffi_closure_SYSV_FS]!
        cfi_adjust_cfa_offset (ffi_closure_SYSV_FS)
        cfi_rel_offset (x29, 0)
Domain: System / Base;