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Re: [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S
- From: Carlos O'Donell <carlos at redhat dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>, libc-alpha at sourceware dot org
- Date: Fri, 6 Jul 2018 10:50:11 -0400
- Subject: Re: [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S
- References: <20180613153207.57232-1-hjl.tools@gmail.com> <20180613153207.57232-6-hjl.tools@gmail.com>
On 06/13/2018 11:31 AM, H.J. Lu wrote:
> Add _CET_ENDBR to functions in dl-tlsdesc.S, which are called indirectly,
> to support IBT.
>
> Tested on i686 and x86-64.
>
> * sysdeps/i386/dl-tlsdesc.S (_dl_tlsdesc_return): Add
> _CET_ENDBR.
> (_dl_tlsdesc_undefweak): Likewise.
> (_dl_tlsdesc_dynamic): Likewise.
> (_dl_tlsdesc_resolve_abs_plus_addend): Likewise.
> (_dl_tlsdesc_resolve_rel): Likewise.
> (_dl_tlsdesc_resolve_rela): Likewise.
> (_dl_tlsdesc_resolve_hold): Likewise.
> * sysdeps/x86_64/dl-tlsdesc.S (_dl_tlsdesc_return): Likewise.
> (_dl_tlsdesc_undefweak): Likewise.
> (_dl_tlsdesc_dynamic): Likewise.
> (_dl_tlsdesc_resolve_rela): Likewise.
> (_dl_tlsdesc_resolve_hold): Likewise.
Please commit.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> sysdeps/i386/dl-tlsdesc.S | 7 +++++++
> sysdeps/x86_64/dl-tlsdesc.S | 5 +++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/sysdeps/i386/dl-tlsdesc.S b/sysdeps/i386/dl-tlsdesc.S
> index 2c4764d1aa..128f0af318 100644
> --- a/sysdeps/i386/dl-tlsdesc.S
> +++ b/sysdeps/i386/dl-tlsdesc.S
> @@ -37,6 +37,7 @@
> cfi_startproc
> .align 16
> _dl_tlsdesc_return:
> + _CET_ENDBR
> movl 4(%eax), %eax
> ret
> cfi_endproc
> @@ -58,6 +59,7 @@ _dl_tlsdesc_return:
> cfi_startproc
> .align 16
> _dl_tlsdesc_undefweak:
> + _CET_ENDBR
> movl 4(%eax), %eax
> subl %gs:0, %eax
> ret
> @@ -99,6 +101,7 @@ _dl_tlsdesc_dynamic (struct tlsdesc *tdp)
> cfi_startproc
> .align 16
> _dl_tlsdesc_dynamic:
> + _CET_ENDBR
> /* Like all TLS resolvers, preserve call-clobbered registers.
> We need two scratch regs anyway. */
> subl $28, %esp
> @@ -154,6 +157,7 @@ _dl_tlsdesc_dynamic:
> .align 16
> _dl_tlsdesc_resolve_abs_plus_addend:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> @@ -192,6 +196,7 @@ _dl_tlsdesc_resolve_abs_plus_addend:
> .align 16
> _dl_tlsdesc_resolve_rel:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> @@ -230,6 +235,7 @@ _dl_tlsdesc_resolve_rel:
> .align 16
> _dl_tlsdesc_resolve_rela:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> @@ -268,6 +274,7 @@ _dl_tlsdesc_resolve_rela:
> .align 16
> _dl_tlsdesc_resolve_hold:
> 0:
> + _CET_ENDBR
> pushl %eax
> cfi_adjust_cfa_offset (4)
> pushl %ecx
> diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S
> index 437bd8cde7..80d771cd88 100644
> --- a/sysdeps/x86_64/dl-tlsdesc.S
> +++ b/sysdeps/x86_64/dl-tlsdesc.S
> @@ -37,6 +37,7 @@
> cfi_startproc
> .align 16
> _dl_tlsdesc_return:
> + _CET_ENDBR
> movq 8(%rax), %rax
> ret
> cfi_endproc
> @@ -58,6 +59,7 @@ _dl_tlsdesc_return:
> cfi_startproc
> .align 16
> _dl_tlsdesc_undefweak:
> + _CET_ENDBR
> movq 8(%rax), %rax
> subq %fs:0, %rax
> ret
> @@ -96,6 +98,7 @@ _dl_tlsdesc_dynamic (register struct tlsdesc *tdp asm ("%rax"))
> cfi_startproc
> .align 16
> _dl_tlsdesc_dynamic:
> + _CET_ENDBR
> /* Preserve call-clobbered registers that we modify.
> We need two scratch regs anyway. */
> movq %rsi, -16(%rsp)
> @@ -166,6 +169,7 @@ _dl_tlsdesc_dynamic:
> .align 16
> /* The PLT entry will have pushed the link_map pointer. */
> _dl_tlsdesc_resolve_rela:
> + _CET_ENDBR
> cfi_adjust_cfa_offset (8)
> /* Save all call-clobbered registers. Add 8 bytes for push in
> the PLT entry to align the stack. */
> @@ -216,6 +220,7 @@ _dl_tlsdesc_resolve_rela:
> .align 16
> _dl_tlsdesc_resolve_hold:
> 0:
> + _CET_ENDBR
> /* Save all call-clobbered registers. */
> subq $72, %rsp
> cfi_adjust_cfa_offset (72)
>
--
Cheers,
Carlos.