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Save & restore the floating-pont argument registers before calling

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_rtld_bind. The compiler may generate code using these registers and not
save them. Unfortunately, as we make use of libc, we are unable to disallow
rtld from using floating-point register without also doing the same for the
parts of libc we use, or by limiting what _rtld_bind is able to call.

Obtained from:	ABT Systems Ltd
Sponsored by:	The FReeBSD Foundation
This commit is contained in:
Andrew Turner 2015-07-02 14:00:07 +00:00
parent fa6e0e5334
commit aeb8eeb590
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=285038
1 changed files with 11 additions and 1 deletions
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12
libexec/rtld-elf/aarch64/rtld_start.S
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@ -70,6 +70,12 @@ ENTRY(_rtld_bind_start)
stp x6, x7, [sp, #-16]!
stp x8, xzr, [sp, #-16]!
/* Save any floating-point arguments */
stp q0, q1, [sp, #-32]!
stp q2, q3, [sp, #-32]!
stp q4, q5, [sp, #-32]!
stp q6, q7, [sp, #-32]!
/* Calculate reloff */
ldr x2, [x17, #0] /* Get the address of the entry */
sub x1, x2, x16 /* Find its offset */
@ -85,12 +91,16 @@ ENTRY(_rtld_bind_start)
bl _rtld_bind
/* Restore the registers saved by the plt code */
ldp xzr, x30, [sp, #(5 * 16)]
ldp xzr, x30, [sp, #(5 * 16 + 4 * 32)]
/* Backup the address to branch to */
mov x16, x0
/* restore the arguments */
ldp q6, q7, [sp], #32
ldp q4, q5, [sp], #32
ldp q2, q3, [sp], #32
ldp q0, q1, [sp], #32
ldp x8, xzr, [sp], #16
ldp x6, x7, [sp], #16
ldp x4, x5, [sp], #16