Re: [PATCH 05/24] x86: Add _CET_ENDBR to functions in dl-tlsdesc.S

[Carlos O'Donell <carlos@redhat.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.