linux-stable.git/tools/include/nolibc, branch linux-6.5.y

tools/nolibc: fix up startup failures for -O0 under gcc < 11.1.0

2023-09-13T07:53:01+00:00

[ Upstream commit bff60150f7c464d80d86f289c056c2ad2afb3c05 ]

As gcc doc [1] shows:

  Most optimizations are completely disabled at -O0 or if an -O level is
  not set on the command line, even if individual optimization flags are
  specified.

Test result [2] shows, gcc>=11.1.0 deviates from the above description,
but before gcc 11.1.0, "-O0" still forcely uses frame pointer in the
_start function even if the individual optimize("omit-frame-pointer")
flag is specified.

The frame pointer related operations will change the stack pointer (e.g.
In x86_64, an extra "push %rbp" will be inserted at the beginning of
_start) and make it differs from the one we expected, as a result, break
the whole startup function.

To fix up this issue, as suggested by Thomas, the individual "Os" and
"omit-frame-pointer" optimize flags are used together on _start function
to disable frame pointer completely even if the -O0 is set on the
command line.

[1]: https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
[2]: https://lore.kernel.org/lkml/20230714094723.140603-1-falcon@tinylab.org/

Suggested-by: Thomas Weißschuh 
Link: https://lore.kernel.org/lkml/34b21ba5-7b59-4b3b-9ed6-ef9a3a5e06f7@t-8ch.de/
Fixes: 7f8548589661 ("tools/nolibc: make compiler and assembler agree on the section around _start")
Signed-off-by: Zhangjin Wu 
Signed-off-by: Willy Tarreau 
Signed-off-by: Sasha Levin

tools/nolibc: arch-*.h: add missing space after ','

2023-09-13T07:53:01+00:00

[ Upstream commit 20233498359a29f7b2ff4e8fbdb0a1a7c8d5744c ]

Fix up such errors reported by scripts/checkpatch.pl:

    ERROR: space required after that ',' (ctx:VxV)
    #148: FILE: tools/include/nolibc/arch-aarch64.h:148:
    +void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_protector _start(void)
                             ^

    ERROR: space required after that ',' (ctx:VxV)
    #148: FILE: tools/include/nolibc/arch-aarch64.h:148:
    +void __attribute__((weak,noreturn,optimize("omit-frame-pointer"))) __no_stack_protector _start(void)
                                      ^

Signed-off-by: Zhangjin Wu 
Signed-off-by: Willy Tarreau 
Stable-dep-of: bff60150f7c4 ("tools/nolibc: fix up startup failures for -O0 under gcc < 11.1.0")
Signed-off-by: Sasha Levin

tools/nolibc: open: fix up compile warning for arm

2023-06-09T18:46:10+00:00

    In function ‘open’:
    nolibc/sysroot/arm/include/sys.h:919:23: warning: ‘mode_t’ {aka ‘short unsigned int’} is promoted to ‘int’ when passed through ‘...’
      919 |   mode = va_arg(args, mode_t);
          |                       ^
    nolibc/sysroot/arm/include/sys.h:919:23: note: (so you should pass ‘int’ not ‘mode_t’ {aka ‘short unsigned int’} to ‘va_arg’)
    nolibc/sysroot/arm/include/sys.h:919:23: note: if this code is reached, the program will abort

Signed-off-by: Zhangjin Wu 
Reviewed-by: Thomas Weißschuh 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

tools/nolibc: arm: add missing my_syscall6

2023-06-09T18:46:09+00:00

This is required by the coming removal of the oldselect and newselect
support.

pselect6/pselect6_time64 will be used unconditionally, they have 6
arguments.

Suggested-by: Arnd Bergmann 
Link: https://lore.kernel.org/linux-riscv/bf3e07c1-75f5-425b-9124-f3f2b230e63a@app.fastmail.com/
Signed-off-by: Zhangjin Wu 
Reviewed-by: Thomas Weißschuh 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: not include limits.h for nolibc

2023-06-09T18:46:09+00:00

When compile nolibc-test.c with 2.31 glibc, we got such error:

    In file included from /usr/riscv64-linux-gnu/include/sys/cdefs.h:452,
                     from /usr/riscv64-linux-gnu/include/features.h:461,
                     from /usr/riscv64-linux-gnu/include/bits/libc-header-start.h:33,
                     from /usr/riscv64-linux-gnu/include/limits.h:26,
                     from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/limits.h:194,
                     from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/syslimits.h:7,
                     from /usr/lib/gcc-cross/riscv64-linux-gnu/9/include/limits.h:34,
                     from /labs/linux-lab/src/linux-stable/tools/testing/selftests/nolibc/nolibc-test.c:6:
    /usr/riscv64-linux-gnu/include/bits/wordsize.h:28:3: error: #error "rv32i-based targets are not supported"
       28 | # error "rv32i-based targets are not supported"

Glibc (>= 2.33) commit 5b6113d62efa ("RISC-V: Support the 32-bit ABI
implementation") fixed up above error.

As suggested by Thomas, defining INT_MIN/INT_MAX for nolibc can remove
the including of limits.h, and therefore no above error. of course, the
other libcs still require limits.h, move it to the right place.

The LONG_MIN/LONG_MAX are also defined too.

Suggested-by: Thomas Weißschuh 
Link: https://lore.kernel.org/linux-riscv/09d60dc2-e298-4c22-8e2f-8375861bd9be@t-8ch.de/
Signed-off-by: Zhangjin Wu 
Reviewed-by: Thomas Weißschuh 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

tools/nolibc: ensure fast64 integer types have 64 bits

2023-06-09T18:46:09+00:00

On 32bit platforms size_t is not enough to represent [u]int_fast64_t.

Fixes: 3e9fd4e9a1d5 ("tools/nolibc: add integer types and integer limit macros")
Signed-off-by: Thomas Weißschuh 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

tools/nolibc: ppoll/ppoll_time64: add a missing argument

2023-06-09T18:46:09+00:00

The ppoll and ppoll_time64 syscalls have 5 arguments, but we only
provide 4, align with kernel and add the missing sigsetsize argument.

Because the sigmask is NULL, the last sigsetsize argument is ignored,
keep it as 0 here is safe enough.

Signed-off-by: Zhangjin Wu 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

tools/nolibc: support nanoseconds in stat()

2023-06-09T18:46:09+00:00

Keep backwards compatibility through unions.

The compatibility macros like

 #define st_atime st_atim.tv_sec

as documented in stat(3type) don't work for nolibc because it would
break with other stat-like structures that contain the field st_atime.

The stx_atime, stx_mtime, stx_ctime are in type of 'struct
statx_timestamp', which is incompatible with 'struct timespec', should
be converted explicitly.

    /* include/uapi/linux/stat.h */

    struct statx_timestamp {
    	__s64	tv_sec;
    	__u32	tv_nsec;
    	__s32	__reserved;
    };

    /* include/uapi/linux/time.h */
    struct timespec {
    	__kernel_old_time_t	tv_sec;		/* seconds */
    	long			tv_nsec;	/* nanoseconds */
    };

Signed-off-by: Thomas Weißschuh 
Link: https://lore.kernel.org/linux-riscv/3a3edd48-1ace-4c89-89e8-9c594dd1b3c9@t-8ch.de/
Co-authored-by: Zhangjin Wu 
Signed-off-by: Zhangjin Wu 
[wt: squashed Zhangjin & Thomas' patches into one to preserve "bisectability"]
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

tools/nolibc: add support for prctl()

2023-06-09T18:46:09+00:00

It will be used to disable core dumps from the child spawned to validate
the stack protector functionality.

Signed-off-by: Thomas Weißschuh 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

tools/nolibc: s390: disable stackprotector in _start

2023-06-09T18:46:09+00:00

s390 does not support the "global" stack protector mode that is
implemented in nolibc.

Now that nolibc detects if stack protectors are enabled at runtime it
could happen that a future compiler does indeed use global mode on
and nolibc would compile but segfault at runtime.

To avoid this hypothetic case and to align s390 with the other
architectures disable stack protectors when compiling _start().

Signed-off-by: Thomas Weißschuh 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney