Re: [Buildroot] [PATCH for-master] package/gcc: 11.3.0: fix glibc crash on G4 ppc cpus

["Yann E. MORIN" <yann.morin.1998@free.fr>]

Romain, All,

On 2022-09-04 15:05 +0200, Romain Naour spake thusly:
> gcc 11.3.0 contains a backported patch [1] that introduce
> a regression for old powerpc cpus like the powerpc 7400 (G4).
> 
> The glibc crash the init process due to a wrong asm machine
> directive (.machine).
> 
> Run /sbin/init as init process
> init[1]: segfault (11) at 7369693e nip 6f6e08 lr 6f6a68 code 1 in libc.so.6[690000+18f000]
> init[1]: code: 280a000c 41c1ffe0 811edb80 554a103a 7d48502e 7d4a4214 7d4903a6 4e800420
> init[1]: code: 2c08007a 4bffffbc 89290000 5529103a <7d2a482e> 2c090000 41c2ff78 7fe4fb78
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> 
> Backport two patches from the gcc-11 stable branch (the upcoming gcc
> 11.4.0).
> 
> [1] https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=3cb53c10831be59d967d9dce8e7980fee4703500
> 
> Fixes:
> https://gitlab.com/kubu93/buildroot/-/jobs/2976071284
> 
> Signed-off-by: Romain Naour <romain.naour@gmail.com>
> Cc: Joel Stanley <joel@jms.id.au>

Applied to master, thanks.

Regards,
Yann E. MORIN.

> ---
>  .../11.3.0/0005-rs6000-Improve-.machine.patch | 120 ++++++++++++++++++
>  ...e-rs6000_cpu-for-.machine-ppc-and-pp.patch |  68 ++++++++++
>  2 files changed, 188 insertions(+)
>  create mode 100644 package/gcc/11.3.0/0005-rs6000-Improve-.machine.patch
>  create mode 100644 package/gcc/11.3.0/0006-rs6000-Do-not-use-rs6000_cpu-for-.machine-ppc-and-pp.patch
> 
> diff --git a/package/gcc/11.3.0/0005-rs6000-Improve-.machine.patch b/package/gcc/11.3.0/0005-rs6000-Improve-.machine.patch
> new file mode 100644
> index 0000000000..7a4564b59e
> --- /dev/null
> +++ b/package/gcc/11.3.0/0005-rs6000-Improve-.machine.patch
> @@ -0,0 +1,120 @@
> +From ca2c3a7d3db7a699c358d3408f820396dd536fc8 Mon Sep 17 00:00:00 2001
> +From: Segher Boessenkool <segher@kernel.crashing.org>
> +Date: Tue, 1 Mar 2022 17:04:29 +0000
> +Subject: [PATCH 5/6] rs6000: Improve .machine
> +
> +This adds more correct .machine for most older CPUs.  It should be
> +conservative in the sense that everything we handled before we handle at
> +least as well now.  This does not yet revamp the server CPU handling, it
> +is too risky at this point in time.
> +
> +Tested on powerpc64-linux {-m32,-m64}.  Also manually tested with all
> +-mcpu=, and the output of that passed through the GNU assembler.
> +
> +2022-03-04  Segher Boessenkool  <segher@kernel.crashing.org>
> +
> +	* config/rs6000/rs6000.c (rs6000_machine_from_flags): Restructure a
> +	bit.  Handle most older CPUs.
> +
> +(cherry picked from commit 77eccbf39ed55297802bb66dff5f62507a7239e3)
> +(cherry picked from commit fc7e603edc67c66a14f893f3b5a0a34e7d26f77c)
> +Signed-off-by: Romain Naour <romain.naour@gmail.com>
> +---
> + gcc/config/rs6000/rs6000.c | 81 +++++++++++++++++++++++++-------------
> + 1 file changed, 54 insertions(+), 27 deletions(-)
> +
> +diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> +index 0421dc7adb3..0a55c979c36 100644
> +--- a/gcc/config/rs6000/rs6000.c
> ++++ b/gcc/config/rs6000/rs6000.c
> +@@ -5742,33 +5742,60 @@ const char *rs6000_machine;
> + const char *
> + rs6000_machine_from_flags (void)
> + {
> +-  /* For some CPUs, the machine cannot be determined by ISA flags.  We have to
> +-     check them first.  */
> +-  switch (rs6000_cpu)
> +-    {
> +-    case PROCESSOR_PPC8540:
> +-    case PROCESSOR_PPC8548:
> +-      return "e500";
> +-
> +-    case PROCESSOR_PPCE300C2:
> +-    case PROCESSOR_PPCE300C3:
> +-      return "e300";
> +-
> +-    case PROCESSOR_PPCE500MC:
> +-      return "e500mc";
> +-
> +-    case PROCESSOR_PPCE500MC64:
> +-      return "e500mc64";
> +-
> +-    case PROCESSOR_PPCE5500:
> +-      return "e5500";
> +-
> +-    case PROCESSOR_PPCE6500:
> +-      return "e6500";
> +-
> +-    default:
> +-      break;
> +-    }
> ++  /* e300 and e500 */
> ++  if (rs6000_cpu == PROCESSOR_PPCE300C2 || rs6000_cpu == PROCESSOR_PPCE300C3)
> ++    return "e300";
> ++  if (rs6000_cpu == PROCESSOR_PPC8540 || rs6000_cpu == PROCESSOR_PPC8548)
> ++    return "e500";
> ++  if (rs6000_cpu == PROCESSOR_PPCE500MC)
> ++    return "e500mc";
> ++  if (rs6000_cpu == PROCESSOR_PPCE500MC64)
> ++    return "e500mc64";
> ++  if (rs6000_cpu == PROCESSOR_PPCE5500)
> ++    return "e5500";
> ++  if (rs6000_cpu == PROCESSOR_PPCE6500)
> ++    return "e6500";
> ++
> ++  /* 400 series */
> ++  if (rs6000_cpu == PROCESSOR_PPC403)
> ++    return "\"403\"";
> ++  if (rs6000_cpu == PROCESSOR_PPC405)
> ++    return "\"405\"";
> ++  if (rs6000_cpu == PROCESSOR_PPC440)
> ++    return "\"440\"";
> ++  if (rs6000_cpu == PROCESSOR_PPC476)
> ++    return "\"476\"";
> ++
> ++  /* A2 */
> ++  if (rs6000_cpu == PROCESSOR_PPCA2)
> ++    return "a2";
> ++
> ++  /* Cell BE */
> ++  if (rs6000_cpu == PROCESSOR_CELL)
> ++    return "cell";
> ++
> ++  /* Titan */
> ++  if (rs6000_cpu == PROCESSOR_TITAN)
> ++    return "titan";
> ++
> ++  /* 500 series and 800 series */
> ++  if (rs6000_cpu == PROCESSOR_MPCCORE)
> ++    return "\"821\"";
> ++
> ++  /* 600 series and 700 series, "classic" */
> ++  if (rs6000_cpu == PROCESSOR_PPC601 || rs6000_cpu == PROCESSOR_PPC603
> ++      || rs6000_cpu == PROCESSOR_PPC604 || rs6000_cpu == PROCESSOR_PPC604e
> ++      || rs6000_cpu == PROCESSOR_PPC750 || rs6000_cpu == PROCESSOR_POWERPC)
> ++    return "ppc";
> ++
> ++  /* Classic with AltiVec, "G4" */
> ++  if (rs6000_cpu == PROCESSOR_PPC7400 || rs6000_cpu == PROCESSOR_PPC7450)
> ++    return "\"7450\"";
> ++
> ++  /* The older 64-bit CPUs */
> ++  if (rs6000_cpu == PROCESSOR_PPC620 || rs6000_cpu == PROCESSOR_PPC630
> ++      || rs6000_cpu == PROCESSOR_RS64A || rs6000_cpu == PROCESSOR_POWERPC64)
> ++    return "ppc64";
> + 
> +   HOST_WIDE_INT flags = rs6000_isa_flags;
> + 
> +-- 
> +2.34.3
> +
> diff --git a/package/gcc/11.3.0/0006-rs6000-Do-not-use-rs6000_cpu-for-.machine-ppc-and-pp.patch b/package/gcc/11.3.0/0006-rs6000-Do-not-use-rs6000_cpu-for-.machine-ppc-and-pp.patch
> new file mode 100644
> index 0000000000..8e31c8241c
> --- /dev/null
> +++ b/package/gcc/11.3.0/0006-rs6000-Do-not-use-rs6000_cpu-for-.machine-ppc-and-pp.patch
> @@ -0,0 +1,68 @@
> +From 6de33ed642f119f1e2543095dd56e4a94f97c27f Mon Sep 17 00:00:00 2001
> +From: Segher Boessenkool <segher@kernel.crashing.org>
> +Date: Fri, 11 Mar 2022 21:15:18 +0000
> +Subject: [PATCH 6/6] rs6000: Do not use rs6000_cpu for .machine ppc and ppc64
> + (PR104829)
> +
> +Fixes: 77eccbf39ed5
> +
> +rs6000.h has
> +  #define PROCESSOR_POWERPC   PROCESSOR_PPC604
> +  #define PROCESSOR_POWERPC64 PROCESSOR_RS64A
> +which means that if you use things like  -mcpu=powerpc -mvsx  it will no
> +longer work after my latest .machine patch.  This causes GCC build errors
> +in some cases, not a good idea (even if the errors are actually
> +pre-existing: using -mvsx with a machine that does not have VSX cannot
> +work properly).
> +
> +2022-03-11  Segher Boessenkool  <segher@kernel.crashing.org>
> +
> +	PR target/104829
> +	* config/rs6000/rs6000.c (rs6000_machine_from_flags): Don't output
> +	"ppc" and "ppc64" based on rs6000_cpu.
> +
> +(cherry picked from commit 80fcc4b6afee72443bef551064826b3b4b6785e6)
> +(cherry picked from commit d87e0e297b1cba73a0c055d2a3e9267d288f435a)
> +Signed-off-by: Romain Naour <romain.naour@gmail.com>
> +---
> + gcc/config/rs6000/rs6000.c | 12 ++++++++++--
> + 1 file changed, 10 insertions(+), 2 deletions(-)
> +
> +diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> +index 0a55c979c36..7e5cdd34840 100644
> +--- a/gcc/config/rs6000/rs6000.c
> ++++ b/gcc/config/rs6000/rs6000.c
> +@@ -5782,20 +5782,28 @@ rs6000_machine_from_flags (void)
> +   if (rs6000_cpu == PROCESSOR_MPCCORE)
> +     return "\"821\"";
> + 
> ++#if 0
> ++  /* This (and ppc64 below) are disabled here (for now at least) because
> ++     PROCESSOR_POWERPC, PROCESSOR_POWERPC64, and PROCESSOR_COMMON
> ++     are #define'd as some of these.  Untangling that is a job for later.  */
> ++
> +   /* 600 series and 700 series, "classic" */
> +   if (rs6000_cpu == PROCESSOR_PPC601 || rs6000_cpu == PROCESSOR_PPC603
> +       || rs6000_cpu == PROCESSOR_PPC604 || rs6000_cpu == PROCESSOR_PPC604e
> +-      || rs6000_cpu == PROCESSOR_PPC750 || rs6000_cpu == PROCESSOR_POWERPC)
> ++      || rs6000_cpu == PROCESSOR_PPC750)
> +     return "ppc";
> ++#endif
> + 
> +   /* Classic with AltiVec, "G4" */
> +   if (rs6000_cpu == PROCESSOR_PPC7400 || rs6000_cpu == PROCESSOR_PPC7450)
> +     return "\"7450\"";
> + 
> ++#if 0
> +   /* The older 64-bit CPUs */
> +   if (rs6000_cpu == PROCESSOR_PPC620 || rs6000_cpu == PROCESSOR_PPC630
> +-      || rs6000_cpu == PROCESSOR_RS64A || rs6000_cpu == PROCESSOR_POWERPC64)
> ++      || rs6000_cpu == PROCESSOR_RS64A)
> +     return "ppc64";
> ++#endif
> + 
> +   HOST_WIDE_INT flags = rs6000_isa_flags;
> + 
> +-- 
> +2.34.3
> +
> -- 
> 2.34.3
> 
> _______________________________________________
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