kernel/arch/sparc/vdso/vclock_gettime.c, branch linux-6.2.y

y2038: vdso: change timespec to __kernel_old_timespec

2019-11-15T13:38:28Z

In order to remove 'timespec' completely from the kernel, all internal uses should be converted to a y2038-safe type, while those that are only for compatibity with existing user space should be marked appropriately. Change vdso to use __kernel_old_timespec in order to avoid the deprecated type and mark these interfaces as outdated. Signed-off-by: Arnd Bergmann

y2038: vdso: change timeval to __kernel_old_timeval

2019-11-15T13:38:27Z

The gettimeofday() function in vdso uses the traditional 'timeval' structure layout, which will be incompatible with future versions of glibc on 32-bit architectures that use a 64-bit time_t. This interface is problematic for y2038, when time_t overflows on 32-bit architectures, but the plan so far is that a libc with 64-bit time_t will not call into the gettimeofday() vdso helper at all, and only have a method for entering clock_gettime(). This means we don't have to fix it here, though we probably want to add a new clock_gettime() entry point using a 64-bit version of 'struct timespec' at some point. Changing the vdso code to use __kernel_old_timeval helps isolate this usage from the other ones that still need to be fixed properly, and it gets us closer to removing the 'timeval' definition from the kernel sources. Reviewed-by: Thomas Gleixner Signed-off-by: Arnd Bergmann

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 223

2019-05-30T18:29:55Z

Based on 1 normalized pattern(s): subject to the gnu public license v 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 9 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Alexios Zavras Reviewed-by: Steve Winslow Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528171440.130801526@linutronix.de Signed-off-by: Greg Kroah-Hartman

sparc: Fix VDSO build with older binutils.

2018-10-25T17:36:19Z

Older versions of bintutils do not allow symbol math across different segments on sparc: ==================== Assembler messages: 99: Error: operation combines symbols in different segments ==================== This is controlled by whether or not DIFF_EXPR_OK is defined in gas/config/tc-*.h and for sparc this was not the case until mid-2017. So we have to patch between %stick and %tick another way. Do what powerpc does and emit two versions of the relevant functions, one using %tick and one using %stick, and patch the symbols in the dynamic symbol table. Fixes: 2f6c9bf31a0b ("sparc: Improve VDSO instruction patching.") Reported-by: Meelis Roos Tested-by: Meelis Roos Signed-off-by: David S. Miller

sparc: Several small VDSO vclock_gettime.c improvements.

2018-10-23T00:42:10Z

Almost entirely borrowed from the x86 code. Main improvement is to avoid having to initialize ts->tv_nsec to zero before the sequence loops, by expanding timespec_add_ns(). Signed-off-by: David S. Miller

sparc: Set DISABLE_BRANCH_PROFILING in VDSO CFLAGS.

2018-10-22T22:51:45Z

Not in vclock_gettime.c itself. Signed-off-by: David S. Miller

sparc: Don't bother masking out TICK_PRIV_BIT in VDSO code.

2018-10-22T22:31:38Z

If the TICK_PRIV_BIT was set, we would not be able to read the tick register in user space, which is where this code runs. Signed-off-by: David S. Miller

sparc: Inline VDSO gettime code aggressively.

2018-10-22T22:27:49Z

One interesting thing we need to do is stop using __builtin_return_address() in get_vvar_data(). Simply read the %pc register instead. Signed-off-by: David S. Miller

sparc: Improve VDSO instruction patching.

2018-10-22T22:22:14Z

The current VDSO patch mechanism has several problems: 1) It assumes how gcc will emit a function, with a register window, an initial save instruction and then immediately the %tick read when compiling vread_tick(). There is no such guarantees, code generation could change at any time, gcc could put a nop between the save and the %tick read, etc. So this is extremely fragile and would fail some day. 2) It disallows us to properly inline vread_tick() into the callers and thus get the best possible code sequences. So fix this to patch properly, with location based annotations. We have to be careful because we cannot do it the way we do patches elsewhere in the kernel. Those use a sequence like: 1: insn .section .whatever_patch, "ax" .word 1b replacement_insn .previous This is a dynamic shared object, so that .word cannot be resolved at build time, and thus cannot be used to execute the patches when the kernel initializes the images. Even trying to use label difference equations doesn't work in the above kind of scheme: 1: insn .section .whatever_patch, "ax" .word . - 1b replacement_insn .previous The assembler complains that it cannot resolve that computation. The issue is that this is contained in an executable section. Borrow the sequence used by x86 alternatives, which is: 1: insn .pushsection .whatever_patch, "a" .word . - 1b, . - 1f .popsection .pushsection .whatever_patch_replacements, "ax" 1: replacement_insn .previous This works, allows us to inline vread_tick() as much as we like, and can be used for arbitrary kinds of VDSO patching in the future. Also, reverse the condition for patching. Most systems are %stick based, so if we only patch on %tick systems the patching code will get little or no testing. Signed-off-by: David S. Miller

sparc: Fix syscall fallback bugs in VDSO.

2018-10-18T04:29:23Z

First, the trap number for 32-bit syscalls is 0x10. Also, only negate the return value when syscall error is indicated by the carry bit being set. Signed-off-by: David S. Miller