[v3,1/4] aarch64: make explicit that CFI gnu_window_save is for Sparc, not AArch64
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| Context |
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| linaro-tcwg-bot/tcwg_binutils_build--master-arm |
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|
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| linaro-tcwg-bot/tcwg_binutils_build--master-aarch64 |
success
|
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|
| linaro-tcwg-bot/tcwg_binutils_check--master-aarch64 |
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|
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|
| linaro-tcwg-bot/tcwg_binutils_check--master-arm |
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|
Test passed
|
Commit Message
- add a detailed comment when parsing DW_CFA_GNU_window_save in SFrame to
explain why we are checking whether the targeted architecture is AArch64,
whereas this CFI is a Sparc extension.
- replace .cfi_gnu_window_save by .cfi_negate_ra_state in existing AArch64
DWARF tests as this is the preferred directive since GCC 15.
- add a new AARch64 test to check backward compatibility with old GCC
versions that emits .cfi_gnu_window_save.
---
gas/gen-sframe.c | 8 +++-
gas/testsuite/gas/aarch64/pac_ab_key.s | 4 +-
.../gas/aarch64/pac_compat_cfi_window_save.d | 44 +++++++++++++++++++
.../gas/aarch64/pac_compat_cfi_window_save.s | 20 +++++++++
4 files changed, 73 insertions(+), 3 deletions(-)
create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
Comments
On 1/13/25 3:22 AM, Matthieu Longo wrote:
> - add a detailed comment when parsing DW_CFA_GNU_window_save in SFrame to
> explain why we are checking whether the targeted architecture is AArch64,
> whereas this CFI is a Sparc extension.
> - replace .cfi_gnu_window_save by .cfi_negate_ra_state in existing AArch64
> DWARF tests as this is the preferred directive since GCC 15.
> - add a new AARch64 test to check backward compatibility with old GCC
Nit: AARch64 -> AArch64
> versions that emits .cfi_gnu_window_save.
> ---
> gas/gen-sframe.c | 8 +++-
> gas/testsuite/gas/aarch64/pac_ab_key.s | 4 +-
> .../gas/aarch64/pac_compat_cfi_window_save.d | 44 +++++++++++++++++++
> .../gas/aarch64/pac_compat_cfi_window_save.s | 20 +++++++++
> 4 files changed, 73 insertions(+), 3 deletions(-)
> create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
> create mode 100644 gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
>
> diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c
> index 71296f2f4fb..a3c40bdd735 100644
> --- a/gas/gen-sframe.c
> +++ b/gas/gen-sframe.c
> @@ -1273,7 +1273,13 @@ sframe_xlate_do_aarch64_negate_ra_state (struct sframe_xlate_ctx *xlate_ctx,
> }
>
> /* Translate DW_CFA_GNU_window_save into SFrame context.
> - DW_CFA_AARCH64_negate_ra_state is multiplexed with DW_CFA_GNU_window_save.
> + DW_CFA_GNU_window_save is a DWARF Sparc extension, but is multiplexed with a
> + directive of DWARF AArch64 extension: DW_CFA_AARCH64_negate_ra_state.
> + The AArch64 backend of GCC 14 and older versions was emitting mistakenly the
> + Sparc CFI directive (.cfi_window_save). From GCC 15, the AArch64 backend
> + only emits .cfi_negate_ra_state. For backward compatibility, the handler for
> + .cfi_window_save needs to check whether the directive was used in a AArch ABI
Nit: AArch -> AArch64 ?
In context of the SFrame changes here, AArch64 should still make sense
(although the multiplexing of directives is applicable to the 32-bit Arm
as well).
OK for the SFrame file changes.
> + context or not.
> Return SFRAME_XLATE_OK if success. */
>
> static int
> diff --git a/gas/testsuite/gas/aarch64/pac_ab_key.s b/gas/testsuite/gas/aarch64/pac_ab_key.s
> index 4b328e72ae4..3b81919409d 100644
> --- a/gas/testsuite/gas/aarch64/pac_ab_key.s
> +++ b/gas/testsuite/gas/aarch64/pac_ab_key.s
> @@ -7,7 +7,7 @@ _Z5foo_av:
> .LFB0:
> .cfi_startproc
> hint 25 // paciasp
> - .cfi_window_save
> + .cfi_negate_ra_state
> stp x29, x30, [sp, -16]!
> .cfi_def_cfa_offset 16
> .cfi_offset 29, -16
> @@ -23,7 +23,7 @@ _Z5foo_bv:
> .cfi_startproc
> .cfi_b_key_frame
> hint 27 // pacibsp
> - .cfi_window_save
> + .cfi_negate_ra_state
> stp x29, x30, [sp, -16]!
> .cfi_def_cfa_offset 16
> .cfi_offset 29, -16
> diff --git a/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
> new file mode 100644
> index 00000000000..8e59086c1b4
> --- /dev/null
> +++ b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
> @@ -0,0 +1,44 @@
> +#objdump: --dwarf=frames
> +# This test is only valid on ELF based ports.
> +#notarget: *-*-*coff *-*-pe *-*-wince *-*-*aout* *-*-netbsd
> +
> +## ARMv8.3 adds support for a new security feature named Pointer Authentication.
> +## The main idea behind this is to use the unused bits in the pointer values.
> +## Each pointer is patched with a PAC before writing to memory, and is verified
> +## before using it.
> +## When the pointers are mangled, the stack trace generator needs to know so it
> +## can mask off the PAC from the pointer value to recover the return address,
> +## and conversely, skip doing so if the pointers are not mangled.
> +##
> +## .cfi_negate_ra_state CFI directive is usually used to convey this information.
> +## .cfi_negate_ra_state and .cfi_window_save are both in the processor-specific
> +## numbering space, but use the same code value in the dwarf tables.
> +## In GCC 14 and older, the Sparc DWARF extension .cfi_window_save is emitted
> +## instead of .cfi_negate_ra_state, but it mapped to the same value. GCC 15 fixed
> +## this naming issue and there is no change to the object file created when the
> +## source is assembled. Nevertheless the support for the SPARC directive is
> +## preserved in binutils for backward compatibility with existing GCC releases,
> +## hence this test.
> +
> +.+: file .+
> +
> +Contents of the .eh_frame section:
> +
> +0+ 0+10 0+ CIE
> + Version: 1
> + Augmentation: "zR"
> + Code alignment factor: 4
> + Data alignment factor: -8
> + Return address column: 30
> + Augmentation data: 1b
> + DW_CFA_def_cfa: r31 \(sp\) ofs 0
> +
> +0+14 0+18 0+18 FDE cie=0+ pc=0+\.\.0+8
> + DW_CFA_advance_loc: 4 to 0+4
> + DW_CFA_AARCH64_negate_ra_state
> + DW_CFA_advance_loc: 4 to 0+8
> + DW_CFA_def_cfa_offset: 16
> + DW_CFA_offset: r29 \(x29\) at cfa-16
> + DW_CFA_offset: r30 \(x30\) at cfa-8
> + DW_CFA_nop
> + DW_CFA_nop
> diff --git a/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
> new file mode 100644
> index 00000000000..92a54f3a344
> --- /dev/null
> +++ b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
> @@ -0,0 +1,20 @@
> + .arch armv8-a
> + .text
> + .align 2
> + .global _Z5foo_av
> + .type _Z5foo_av, %function
> +_Z5foo_av:
> +.LFB0:
> + .cfi_startproc
> + hint 25 // paciasp
> + .cfi_window_save // really .cfi_negate_ra_state
> + stp x29, x30, [sp, -16]!
> + .cfi_def_cfa_offset 16
> + .cfi_offset 29, -16
> + .cfi_offset 30, -8
> + .cfi_endproc
> +.LFE0:
> + .size _Z5foo_av, .-_Z5foo_av
> + .align 2
> + .global _Z5foo_bv
> + .type _Z5foo_bv, %function
On 2025-01-13 23:10, Indu Bhagat wrote:
> On 1/13/25 3:22 AM, Matthieu Longo wrote:
>> - add a detailed comment when parsing DW_CFA_GNU_window_save in SFrame to
>> explain why we are checking whether the targeted architecture is
>> AArch64,
>> whereas this CFI is a Sparc extension.
>> - replace .cfi_gnu_window_save by .cfi_negate_ra_state in existing
>> AArch64
>> DWARF tests as this is the preferred directive since GCC 15.
>> - add a new AARch64 test to check backward compatibility with old GCC
>
> Nit: AARch64 -> AArch64
>
Fixed.
>> versions that emits .cfi_gnu_window_save.
>> ---
>> gas/gen-sframe.c | 8 +++-
>> gas/testsuite/gas/aarch64/pac_ab_key.s | 4 +-
>> .../gas/aarch64/pac_compat_cfi_window_save.d | 44 +++++++++++++++++++
>> .../gas/aarch64/pac_compat_cfi_window_save.s | 20 +++++++++
>> 4 files changed, 73 insertions(+), 3 deletions(-)
>> create mode 100644 gas/testsuite/gas/aarch64/
>> pac_compat_cfi_window_save.d
>> create mode 100644 gas/testsuite/gas/aarch64/
>> pac_compat_cfi_window_save.s
>>
>> diff --git a/gas/gen-sframe.c b/gas/gen-sframe.c
>> index 71296f2f4fb..a3c40bdd735 100644
>> --- a/gas/gen-sframe.c
>> +++ b/gas/gen-sframe.c
>> @@ -1273,7 +1273,13 @@ sframe_xlate_do_aarch64_negate_ra_state (struct
>> sframe_xlate_ctx *xlate_ctx,
>> }
>> /* Translate DW_CFA_GNU_window_save into SFrame context.
>> - DW_CFA_AARCH64_negate_ra_state is multiplexed with
>> DW_CFA_GNU_window_save.
>> + DW_CFA_GNU_window_save is a DWARF Sparc extension, but is
>> multiplexed with a
>> + directive of DWARF AArch64 extension: DW_CFA_AARCH64_negate_ra_state.
>> + The AArch64 backend of GCC 14 and older versions was emitting
>> mistakenly the
>> + Sparc CFI directive (.cfi_window_save). From GCC 15, the AArch64
>> backend
>> + only emits .cfi_negate_ra_state. For backward compatibility, the
>> handler for
>> + .cfi_window_save needs to check whether the directive was used in
>> a AArch ABI
>
> Nit: AArch -> AArch64 ?
Fixed.
> In context of the SFrame changes here, AArch64 should still make sense
> (although the multiplexing of directives is applicable to the 32-bit Arm
> as well).
>
> OK for the SFrame file changes.
Thanks.
>> + context or not.
>> Return SFRAME_XLATE_OK if success. */
>> static int
>> diff --git a/gas/testsuite/gas/aarch64/pac_ab_key.s b/gas/testsuite/
>> gas/aarch64/pac_ab_key.s
>> index 4b328e72ae4..3b81919409d 100644
>> --- a/gas/testsuite/gas/aarch64/pac_ab_key.s
>> +++ b/gas/testsuite/gas/aarch64/pac_ab_key.s
>> @@ -7,7 +7,7 @@ _Z5foo_av:
>> .LFB0:
>> .cfi_startproc
>> hint 25 // paciasp
>> - .cfi_window_save
>> + .cfi_negate_ra_state
>> stp x29, x30, [sp, -16]!
>> .cfi_def_cfa_offset 16
>> .cfi_offset 29, -16
>> @@ -23,7 +23,7 @@ _Z5foo_bv:
>> .cfi_startproc
>> .cfi_b_key_frame
>> hint 27 // pacibsp
>> - .cfi_window_save
>> + .cfi_negate_ra_state
>> stp x29, x30, [sp, -16]!
>> .cfi_def_cfa_offset 16
>> .cfi_offset 29, -16
>> diff --git a/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d b/
>> gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
>> new file mode 100644
>> index 00000000000..8e59086c1b4
>> --- /dev/null
>> +++ b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.d
>> @@ -0,0 +1,44 @@
>> +#objdump: --dwarf=frames
>> +# This test is only valid on ELF based ports.
>> +#notarget: *-*-*coff *-*-pe *-*-wince *-*-*aout* *-*-netbsd
>> +
>> +## ARMv8.3 adds support for a new security feature named Pointer
>> Authentication.
>> +## The main idea behind this is to use the unused bits in the pointer
>> values.
>> +## Each pointer is patched with a PAC before writing to memory, and
>> is verified
>> +## before using it.
>> +## When the pointers are mangled, the stack trace generator needs to
>> know so it
>> +## can mask off the PAC from the pointer value to recover the return
>> address,
>> +## and conversely, skip doing so if the pointers are not mangled.
>> +##
>> +## .cfi_negate_ra_state CFI directive is usually used to convey this
>> information.
>> +## .cfi_negate_ra_state and .cfi_window_save are both in the
>> processor-specific
>> +## numbering space, but use the same code value in the dwarf tables.
>> +## In GCC 14 and older, the Sparc DWARF extension .cfi_window_save is
>> emitted
>> +## instead of .cfi_negate_ra_state, but it mapped to the same value.
>> GCC 15 fixed
>> +## this naming issue and there is no change to the object file
>> created when the
>> +## source is assembled. Nevertheless the support for the SPARC
>> directive is
>> +## preserved in binutils for backward compatibility with existing GCC
>> releases,
>> +## hence this test.
>> +
>> +.+: file .+
>> +
>> +Contents of the .eh_frame section:
>> +
>> +0+ 0+10 0+ CIE
>> + Version: 1
>> + Augmentation: "zR"
>> + Code alignment factor: 4
>> + Data alignment factor: -8
>> + Return address column: 30
>> + Augmentation data: 1b
>> + DW_CFA_def_cfa: r31 \(sp\) ofs 0
>> +
>> +0+14 0+18 0+18 FDE cie=0+ pc=0+\.\.0+8
>> + DW_CFA_advance_loc: 4 to 0+4
>> + DW_CFA_AARCH64_negate_ra_state
>> + DW_CFA_advance_loc: 4 to 0+8
>> + DW_CFA_def_cfa_offset: 16
>> + DW_CFA_offset: r29 \(x29\) at cfa-16
>> + DW_CFA_offset: r30 \(x30\) at cfa-8
>> + DW_CFA_nop
>> + DW_CFA_nop
>> diff --git a/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s b/
>> gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
>> new file mode 100644
>> index 00000000000..92a54f3a344
>> --- /dev/null
>> +++ b/gas/testsuite/gas/aarch64/pac_compat_cfi_window_save.s
>> @@ -0,0 +1,20 @@
>> + .arch armv8-a
>> + .text
>> + .align 2
>> + .global _Z5foo_av
>> + .type _Z5foo_av, %function
>> +_Z5foo_av:
>> +.LFB0:
>> + .cfi_startproc
>> + hint 25 // paciasp
>> + .cfi_window_save // really .cfi_negate_ra_state
>> + stp x29, x30, [sp, -16]!
>> + .cfi_def_cfa_offset 16
>> + .cfi_offset 29, -16
>> + .cfi_offset 30, -8
>> + .cfi_endproc
>> +.LFE0:
>> + .size _Z5foo_av, .-_Z5foo_av
>> + .align 2
>> + .global _Z5foo_bv
>> + .type _Z5foo_bv, %function
>
@@ -1273,7 +1273,13 @@ sframe_xlate_do_aarch64_negate_ra_state (struct sframe_xlate_ctx *xlate_ctx,
}
/* Translate DW_CFA_GNU_window_save into SFrame context.
- DW_CFA_AARCH64_negate_ra_state is multiplexed with DW_CFA_GNU_window_save.
+ DW_CFA_GNU_window_save is a DWARF Sparc extension, but is multiplexed with a
+ directive of DWARF AArch64 extension: DW_CFA_AARCH64_negate_ra_state.
+ The AArch64 backend of GCC 14 and older versions was emitting mistakenly the
+ Sparc CFI directive (.cfi_window_save). From GCC 15, the AArch64 backend
+ only emits .cfi_negate_ra_state. For backward compatibility, the handler for
+ .cfi_window_save needs to check whether the directive was used in a AArch ABI
+ context or not.
Return SFRAME_XLATE_OK if success. */
static int
@@ -7,7 +7,7 @@ _Z5foo_av:
.LFB0:
.cfi_startproc
hint 25 // paciasp
- .cfi_window_save
+ .cfi_negate_ra_state
stp x29, x30, [sp, -16]!
.cfi_def_cfa_offset 16
.cfi_offset 29, -16
@@ -23,7 +23,7 @@ _Z5foo_bv:
.cfi_startproc
.cfi_b_key_frame
hint 27 // pacibsp
- .cfi_window_save
+ .cfi_negate_ra_state
stp x29, x30, [sp, -16]!
.cfi_def_cfa_offset 16
.cfi_offset 29, -16
new file mode 100644
@@ -0,0 +1,44 @@
+#objdump: --dwarf=frames
+# This test is only valid on ELF based ports.
+#notarget: *-*-*coff *-*-pe *-*-wince *-*-*aout* *-*-netbsd
+
+## ARMv8.3 adds support for a new security feature named Pointer Authentication.
+## The main idea behind this is to use the unused bits in the pointer values.
+## Each pointer is patched with a PAC before writing to memory, and is verified
+## before using it.
+## When the pointers are mangled, the stack trace generator needs to know so it
+## can mask off the PAC from the pointer value to recover the return address,
+## and conversely, skip doing so if the pointers are not mangled.
+##
+## .cfi_negate_ra_state CFI directive is usually used to convey this information.
+## .cfi_negate_ra_state and .cfi_window_save are both in the processor-specific
+## numbering space, but use the same code value in the dwarf tables.
+## In GCC 14 and older, the Sparc DWARF extension .cfi_window_save is emitted
+## instead of .cfi_negate_ra_state, but it mapped to the same value. GCC 15 fixed
+## this naming issue and there is no change to the object file created when the
+## source is assembled. Nevertheless the support for the SPARC directive is
+## preserved in binutils for backward compatibility with existing GCC releases,
+## hence this test.
+
+.+: file .+
+
+Contents of the .eh_frame section:
+
+0+ 0+10 0+ CIE
+ Version: 1
+ Augmentation: "zR"
+ Code alignment factor: 4
+ Data alignment factor: -8
+ Return address column: 30
+ Augmentation data: 1b
+ DW_CFA_def_cfa: r31 \(sp\) ofs 0
+
+0+14 0+18 0+18 FDE cie=0+ pc=0+\.\.0+8
+ DW_CFA_advance_loc: 4 to 0+4
+ DW_CFA_AARCH64_negate_ra_state
+ DW_CFA_advance_loc: 4 to 0+8
+ DW_CFA_def_cfa_offset: 16
+ DW_CFA_offset: r29 \(x29\) at cfa-16
+ DW_CFA_offset: r30 \(x30\) at cfa-8
+ DW_CFA_nop
+ DW_CFA_nop
new file mode 100644
@@ -0,0 +1,20 @@
+ .arch armv8-a
+ .text
+ .align 2
+ .global _Z5foo_av
+ .type _Z5foo_av, %function
+_Z5foo_av:
+.LFB0:
+ .cfi_startproc
+ hint 25 // paciasp
+ .cfi_window_save // really .cfi_negate_ra_state
+ stp x29, x30, [sp, -16]!
+ .cfi_def_cfa_offset 16
+ .cfi_offset 29, -16
+ .cfi_offset 30, -8
+ .cfi_endproc
+.LFE0:
+ .size _Z5foo_av, .-_Z5foo_av
+ .align 2
+ .global _Z5foo_bv
+ .type _Z5foo_bv, %function