linux/arch/alpha, branch v6.3

alpha: fix lazy-FPU mis(merged/applied/whatnot)

2023-03-07T01:13:49Z

Looks like a braino that used to be fixed in e.g. #next.alpha had gotten into alpha.git cherry-picked version of that patch. Sure, alpha has no preempt, but preempt_enable() in place of preempt_disable() is actively confusing the readers... Other than that, the cherry-picked variant matches what I have. Signed-off-by: Al Viro

Merge tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2023-03-05T19:07:58Z

Pull VM_FAULT_RETRY fixes from Al Viro: "Some of the page fault handlers do not deal with the following case correctly: - handle_mm_fault() has returned VM_FAULT_RETRY - there is a pending fatal signal - fault had happened in kernel mode Correct action in such case is not "return unconditionally" - fatal signals are handled only upon return to userland and something like copy_to_user() would end up retrying the faulting instruction and triggering the same fault again and again. What we need to do in such case is to make the caller to treat that as failed uaccess attempt - handle exception if there is an exception handler for faulting instruction or oops if there isn't one. Over the years some architectures had been fixed and now are handling that case properly; some still do not. This series should fix the remaining ones. Status: - m68k, riscv, hexagon, parisc: tested/acked by maintainers. - alpha, sparc32, sparc64: tested locally - bug has been reproduced on the unpatched kernel and verified to be fixed by this series. - ia64, microblaze, nios2, openrisc: build, but otherwise completely untested" * tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: openrisc: fix livelock in uaccess nios2: fix livelock in uaccess microblaze: fix livelock in uaccess ia64: fix livelock in uaccess sparc: fix livelock in uaccess alpha: fix livelock in uaccess parisc: fix livelock in uaccess hexagon: fix livelock in uaccess riscv: fix livelock in uaccess m68k: fix livelock in uaccess

alpha: fix livelock in uaccess

2023-03-02T17:32:15Z

alpha equivalent of 26178ec11ef3 "x86: mm: consolidate VM_FAULT_RETRY handling" If e.g. get_user() triggers a page fault and a fatal signal is caught, we might end up with handle_mm_fault() returning VM_FAULT_RETRY and not doing anything to page tables. In such case we must *not* return to the faulting insn - that would repeat the entire thing without making any progress; what we need instead is to treat that as failed (user) memory access. Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha

2023-02-25T20:49:29Z

Pull alpha updates from Al Viro: "Mostly small janitorial fixes but there's also more important ones: a patch to fix loading large modules from Edward Humes, and some fixes from Al Viro" [ The fixes from Al mostly came in separately through Al's trees too and are now duplicated.. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha: alpha: in_irq() cleanup alpha: lazy FPU switching alpha/boot/misc: trim unused declarations alpha/boot/tools/objstrip: fix the check for ELF header alpha/boot: fix the breakage from -isystem series... alpha: fix FEN fault handling alpha: Avoid comma separated statements alpha: fixed a typo in core_cia.c alpha: remove unused __SLOW_DOWN_IO and SLOW_DOWN_IO definitions alpha: update config files alpha: fix R_ALPHA_LITERAL reloc for large modules alpha: Add some spaces to ensure format specification alpha: replace NR_SYSCALLS by NR_syscalls alpha: Remove redundant local asm header redirections alpha: Implement "current_stack_pointer" alpha: remove redundant err variable alpha: osf_sys: reduce kernel log spamming on invalid osf_mount call typenr

alpha: in_irq() cleanup

2023-02-25T04:14:22Z

Replace the obsolete and ambiguos macro in_irq() with new macro in_hardirq(). Signed-off-by: Changbin Du Signed-off-by: Matt Turner

alpha: lazy FPU switching

2023-02-25T04:14:22Z

On each context switch we save the FPU registers on stack of old process and restore FPU registers from the stack of new one. That allows us to avoid doing that each time we enter/leave the kernel mode; however, that can get suboptimal in some cases. For one thing, we don't need to bother saving anything for kernel threads. For another, if between entering and leaving the kernel a thread gives CPU up more than once, it will do useless work, saving the same values every time, only to discard the saved copy as soon as it returns from switch_to(). Alternative solution: * move the array we save into from switch_stack to thread_info * have a (thread-synchronous) flag set when we save them * have another flag set when they should be restored on return to userland. * do *NOT* save/restore them in do_switch_stack()/undo_switch_stack(). * restore on the exit to user mode if the restore flag had been set. Clear both flags. * on context switch, entry to fork/clone/vfork, before entry into do_signal() and on entry into straced syscall save the registers and set the 'saved' flag unless it had been already set. * on context switch set the 'restore' flag as well. * have copy_thread() set both flags for child, so the registers would be restored once the child returns to userland. * use the saved data in setup_sigcontext(); have restore_sigcontext() set both flags and copy from sigframe to save area. * teach ptrace to look for FPU registers in thread_info instead of switch_stack. * teach isolated accesses to FPU registers (rdfpcr, wrfpcr, etc.) to check the 'saved' flag (under preempt_disable()) and work with the save area if it's been set; if 'saved' flag is found upon write access, set 'restore' flag as well. Signed-off-by: Al Viro Signed-off-by: Matt Turner

alpha/boot/misc: trim unused declarations

2023-02-25T04:14:22Z

gzip_mark() and gzip_release() are gone; there used to be two forward declarations of each and the patch removing those suckers had left one of each behind... Signed-off-by: Al Viro Signed-off-by: Matt Turner

alpha/boot/tools/objstrip: fix the check for ELF header

2023-02-25T04:14:22Z

Just memcmp() with ELFMAG - that's the normal way to do it in userland code, which that thing is. Besides, that has the benefit of actually building - str_has_prefix() is *NOT* present in . Fixes: 5f14596e55de "alpha: Replace strncmp with str_has_prefix" Signed-off-by: Al Viro Signed-off-by: Matt Turner

alpha/boot: fix the breakage from -isystem series...

2023-02-25T04:14:22Z

Signed-off-by: Al Viro Signed-off-by: Matt Turner

alpha: fix FEN fault handling

2023-02-25T04:14:22Z

Type 3 instruction fault (FPU insn with FPU disabled) is handled by quietly enabling FPU and returning. Which is fine, except that we need to do that both for fault in userland and in the kernel; the latter *can* legitimately happen - all it takes is this: .global _start _start: call_pal 0xae lda $0, 0 ldq $0, 0($0) - call_pal CLRFEN to clear "FPU enabled" flag and arrange for a signal delivery (SIGSEGV in this case). Fixed by moving the handling of type 3 into the common part of do_entIF(), before we check for kernel vs. user mode. Incidentally, check for kernel mode is unidiomatic; the normal way to do that is !user_mode(regs). The difference is that the open-coded variant treats any of bits 63..3 of regs->ps being set as "it's user mode" while the normal approach is to check just the bit 3. PS is a 4-bit register and regs->ps always will have bits 63..4 clear, so the open-code variant here is actually equivalent to !user_mode(regs). Harder to follow, though... Reproducer above will crash any box where CLRFEN is not ignored by PAL (== any actual hardware, AFAICS; PAL used in qemu doesn't bother implementing that crap). Cc: stable@vger.kernel.org # all way back... Reviewed-by: Richard Henderson Signed-off-by: Al Viro Signed-off-by: Matt Turner