base/regdump-arm64.S, base/regdump.h: Save NZCV and x8--x15 early.

Alas, the processor flags /and/ at least x14 and x15 are clobbered by
the PLT on-demand linkage machinery, so we must save them in the macro
before calling out to the library.  To be safe, preserve all of the
non-argument call-clobbered registers.

diff --git a/base/regdump-arm64.S b/base/regdump-arm64.S
index 81c9f8e..183d38f 100644 (file)
--- a/base/regdump-arm64.S
+++ b/base/regdump-arm64.S
@@ -56,10 +56,6 @@ FUNC(regdump_gpsave)
        stp     x2, x3, [sp, #16]
        stp     x4, x5, [sp, #32]
        stp     x6, x7, [sp, #48]
        stp     x2, x3, [sp, #16]
        stp     x4, x5, [sp, #32]
        stp     x6, x7, [sp, #48]

-       stp     x8, x9, [sp, #64]
-       stp     x10, x11, [sp, #80]
-       stp     x12, x13, [sp, #96]
-       stp     x14, x15, [sp, #112]

        stp     x18, x19, [sp, #144]
        stp     x20, x21, [sp, #160]
        stp     x22, x23, [sp, #176]
        stp     x18, x19, [sp, #144]
        stp     x20, x21, [sp, #160]
        stp     x22, x23, [sp, #176]


@@ -73,10 +69,6 @@ FUNC(regdump_gpsave)
        add     x0, x20, #REGDUMP_GPSIZE
        str     x0, [x20, #31*8]
 
        add     x0, x20, #REGDUMP_GPSIZE
        str     x0, [x20, #31*8]
 

-       // Capture the status flags.
-       mrs     x0, nzcv
-       str     x0, [x20, #8*REGIX_NZCV]
-

        // Set the return address as our PC.
        str     x30, [x20, #8*REGIX_PC]
 
        // Set the return address as our PC.
        str     x30, [x20, #8*REGIX_PC]
 

diff --git a/base/regdump.h b/base/regdump.h
index a07072d..3a6d59c 100644 (file)
--- a/base/regdump.h
+++ b/base/regdump.h
@@ -774,8 +774,15 @@ DO32(REGDEF_FP)
        // Make space for the register save area.
        sub     sp, sp, #REGDUMP_GPSIZE
 
        // Make space for the register save area.
        sub     sp, sp, #REGDUMP_GPSIZE
 

-       // Save flags and general-purpose registers.
-       stp     x16, x17, [sp, #8*16]
+       // Save flags and general-purpose registers.  The PLT linkage code
+       // makes free with x8--x17, so we must save those here.
+       mrs     x30, nzcv
+       str     x30, [sp, #8*REGIX_NZCV]
+       stp     x8, x9, [sp, #64]
+       stp     x10, x11, [sp, #80]
+       stp     x12, x13, [sp, #96]
+       stp     x14, x15, [sp, #112]
+       stp     x16, x17, [sp, #128]

        bl      regdump_gpsave
 
        // Make space for the extended registers.
        bl      regdump_gpsave
 
        // Make space for the extended registers.