Re: [PATCH] libc/arm: add missing .cfi_sections

@Richard, any input from arm.com?


Thanks,
Corinna


On Jul  4 13:44, Clément Chigot wrote:
> On Mon, Jun 10, 2024 at 2:38 PM Clément Chigot <[email protected]> wrote:
> >
> > The modifications added by the series "M-profile PACBTI-enablement"
> > (see 9d6b00511e50a54d2472d11f75f7c0f2b4a98b24) have introduced a couple
> > of .cfi_* instructions.
> >
> > Like for e6459123e497409a9e3d845c39829a9602ba55a4, these instructions
> > create object files which contain .eh_frame sections.  However, ARM uses
> > its own unwind info format, not .eh_frame, which is generated by
> > ARM-specific directives, not .cfi_*. The .eh_frame sections are useless,
> > but also not removed by strip and may be harmful with some linker
> > scripts.
> >
> > Adding ".cfi_sections .debug_frame" (as in glibc) moves the generated
> > directives towards .debug_frame instead of .eh_frame. Making them easier
> > to handle.
> >
> >             * libc/machine/arm/aeabi_memmove-thumb2.S: Use .cfi_sections
> >             .debug_frame.
> >             * libc/machine/arm/aeabi_memset-thumb2.S: Likewise.
> >             * libc/machine/arm/memchr.S: Likewise.
> >             * libc/machine/arm/memcpy-armv7m.S: Likewise.
> >             * libc/machine/arm/setjmp.S: Likewise.
> >             * libc/machine/arm/strlen-armv7.S: Likewise.
> >             * libc/machine/arm/strlen-thumb2-Os.S: Likewise.
> 
> Gentle ping
> 
> > ---
> >  newlib/libc/machine/arm/aeabi_memmove-thumb2.S | 1 +
> >  newlib/libc/machine/arm/aeabi_memset-thumb2.S  | 1 +
> >  newlib/libc/machine/arm/memchr.S               | 1 +
> >  newlib/libc/machine/arm/memcpy-armv7m.S        | 1 +
> >  newlib/libc/machine/arm/setjmp.S               | 1 +
> >  newlib/libc/machine/arm/strlen-armv7.S         | 1 +
> >  newlib/libc/machine/arm/strlen-thumb2-Os.S     | 1 +
> >  7 files changed, 7 insertions(+)
> >
> > diff --git a/newlib/libc/machine/arm/aeabi_memmove-thumb2.S b/newlib/libc/machine/arm/aeabi_memmove-thumb2.S
> > index 20ca993e5..3018e7412 100644
> > --- a/newlib/libc/machine/arm/aeabi_memmove-thumb2.S
> > +++ b/newlib/libc/machine/arm/aeabi_memmove-thumb2.S
> > @@ -36,6 +36,7 @@
> >         ASM_ALIAS __aeabi_memmove8 __aeabi_memmove
> >  __aeabi_memmove:
> >         .fnstart
> > +       .cfi_sections .debug_frame
> >         .cfi_startproc
> >         prologue 4
> >         cmp     r0, r1
> > diff --git a/newlib/libc/machine/arm/aeabi_memset-thumb2.S b/newlib/libc/machine/arm/aeabi_memset-thumb2.S
> > index 6b77d3820..a1b8f0532 100644
> > --- a/newlib/libc/machine/arm/aeabi_memset-thumb2.S
> > +++ b/newlib/libc/machine/arm/aeabi_memset-thumb2.S
> > @@ -33,6 +33,7 @@
> >         .global __aeabi_memset
> >         .type   __aeabi_memset, %function
> >         .fnstart
> > +       .cfi_sections .debug_frame
> >         .cfi_startproc
> >         ASM_ALIAS __aeabi_memset4 __aeabi_memset
> >         ASM_ALIAS __aeabi_memset8 __aeabi_memset
> > diff --git a/newlib/libc/machine/arm/memchr.S b/newlib/libc/machine/arm/memchr.S
> > index d13ef8d65..f0b3650aa 100644
> > --- a/newlib/libc/machine/arm/memchr.S
> > +++ b/newlib/libc/machine/arm/memchr.S
> > @@ -293,6 +293,7 @@ memchr:
> >         .global memchr
> >         .type memchr,%function
> >         .fnstart
> > +       .cfi_sections .debug_frame
> >         .cfi_startproc
> >  memchr:
> >         @ r0 = start of memory to scan
> > diff --git a/newlib/libc/machine/arm/memcpy-armv7m.S b/newlib/libc/machine/arm/memcpy-armv7m.S
> > index ec1ad6485..13ffdb343 100644
> > --- a/newlib/libc/machine/arm/memcpy-armv7m.S
> > +++ b/newlib/libc/machine/arm/memcpy-armv7m.S
> > @@ -88,6 +88,7 @@
> >         .thumb
> >         .thumb_func
> >         .fnstart
> > +       .cfi_sections .debug_frame
> >         .cfi_startproc
> >         .type   memcpy, %function
> >  memcpy:
> > diff --git a/newlib/libc/machine/arm/setjmp.S b/newlib/libc/machine/arm/setjmp.S
> > index 5e5952296..0070f17cd 100644
> > --- a/newlib/libc/machine/arm/setjmp.S
> > +++ b/newlib/libc/machine/arm/setjmp.S
> > @@ -183,6 +183,7 @@ SYM (.arm_start_of.\name):
> >         MODE
> >         .globl SYM (\name)
> >         .fnstart
> > +       .cfi_sections .debug_frame
> >         .cfi_startproc
> >         TYPE (\name)
> >  SYM (\name):
> > diff --git a/newlib/libc/machine/arm/strlen-armv7.S b/newlib/libc/machine/arm/strlen-armv7.S
> > index 6aa122c07..1c2b5c532 100644
> > --- a/newlib/libc/machine/arm/strlen-armv7.S
> > +++ b/newlib/libc/machine/arm/strlen-armv7.S
> > @@ -106,6 +106,7 @@
> >
> >  def_fn strlen p2align=6
> >         .fnstart
> > +       .cfi_sections .debug_frame
> >         .cfi_startproc
> >         prologue 4 5 push_ip=HAVE_PAC_LEAF
> >         pld     [srcin, #0]
> > diff --git a/newlib/libc/machine/arm/strlen-thumb2-Os.S b/newlib/libc/machine/arm/strlen-thumb2-Os.S
> > index 4adbc61d2..b8a615a15 100644
> > --- a/newlib/libc/machine/arm/strlen-thumb2-Os.S
> > +++ b/newlib/libc/machine/arm/strlen-thumb2-Os.S
> > @@ -47,6 +47,7 @@
> >
> >  def_fn strlen p2align=1
> >         .fnstart
> > +       .cfi_sections .debug_frame
> >         .cfi_startproc
> >         prologue
> >         mov     r3, r0
> > --
> > 2.25.1
> >