kernel/linux.git/arch/powerpc/mm/fault.c, branch linux-4.16.y

Merge branch 'fixes' into next

2018-01-21T12:21:14+00:00

Merge our fixes branch from the 4.15 cycle. Unusually the fixes branch saw some significant features merged, notably the RFI flush patches, so we want the code in next to be tested against that, to avoid any surprises when the two are merged. There's also some other work on the panic handling that was reverted in fixes and we now want to do properly in next, which would conflict. And we also fix a few other minor merge conflicts.

powerpc: Deliver SEGV signal on pkey violation

2018-01-20T11:59:05+00:00

The value of the pkey, whose protection got violated, is made available in si_pkey field of the siginfo structure. Signed-off-by: Ram Pai Signed-off-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman

powerpc: Handle exceptions caused by pkey violation

2018-01-20T11:59:04+00:00

Handle Data and Instruction exceptions caused by memory protection-key. The CPU will detect the key fault if the HPTE is already programmed with the key. However if the HPTE is not hashed, a key fault will not be detected by the hardware. The software will detect pkey violation in such a case. Signed-off-by: Ram Pai Signed-off-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman

powerpc: Use the TRAP macro whenever comparing a trap number

2018-01-16T12:51:43+00:00

Trap numbers can have extra bits at the bottom that need to be filtered out. There are a few cases where we don't do that. It's possible that we got lucky but better safe than sorry. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman

powerpc/mm: Fix SEGV on mapped region to return SEGV_ACCERR

2018-01-02T10:12:33+00:00

The recent refactoring of the powerpc page fault handler in commit c3350602e876 ("powerpc/mm: Make bad_area* helper functions") caused access to protected memory regions to indicate SEGV_MAPERR instead of the traditional SEGV_ACCERR in the si_code field of a user-space signal handler. This can confuse debug libraries that temporarily change the protection of memory regions, and expect to use SEGV_ACCERR as an indication to restore access to a region. This commit restores the previous behavior. The following program exhibits the issue: $ ./repro read || echo "FAILED" $ ./repro write || echo "FAILED" $ ./repro exec || echo "FAILED" #include #include #include #include #include #include #include static void segv_handler(int n, siginfo_t *info, void *arg) { _exit(info->si_code == SEGV_ACCERR ? 0 : 1); } int main(int argc, char **argv) { void *p = NULL; struct sigaction act = { .sa_sigaction = segv_handler, .sa_flags = SA_SIGINFO, }; assert(argc == 2); p = mmap(NULL, getpagesize(), (strcmp(argv[1], "write") == 0) ? PROT_READ : 0, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); assert(p != MAP_FAILED); assert(sigaction(SIGSEGV, &act, NULL) == 0); if (strcmp(argv[1], "read") == 0) printf("%c", *(unsigned char *)p); else if (strcmp(argv[1], "write") == 0) *(unsigned char *)p = 0; else if (strcmp(argv[1], "exec") == 0) ((void (*)(void))p)(); return 1; /* failed to generate SEGV */ } Fixes: c3350602e876 ("powerpc/mm: Make bad_area* helper functions") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: John Sperbeck Acked-by: Benjamin Herrenschmidt [mpe: Add commit references in change log] Signed-off-by: Michael Ellerman

powerpc/8xx: Use symbolic names for DSISR bits in DSI

2017-08-10T13:32:20+00:00

Use symbolic names for DSISR bits in DSI Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc/8xx: Getting rid of remaining use of CONFIG_8xx

2017-08-10T13:32:12+00:00

Two config options exist to define powerpc MPC8xx: * CONFIG_PPC_8xx * CONFIG_8xx arch/powerpc/platforms/Kconfig.cputype has contained the following comment about CONFIG_8xx item for some years: "# this is temp to handle compat with arch=ppc" arch/powerpc is now the only place with remaining use of CONFIG_8xx: get rid of them. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman

powerpc: Remove old unused icswx based coprocessor support

2017-08-03T06:06:52+00:00

We have a whole pile of unused code to maintain the ACOP register, allocate coprocessor PIDs and handle ACOP faults. This mechanism was used for the HFI adapter on POWER7 which is dead and gone and whose driver never went upstream. It was used on some A2 core based stuff that also never saw the light of day. Take out all that code. There is still some POWER8 coprocessor code that uses icswx but it's kernel only and thus doesn't use any of that infrastructure. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman

powerpc/mm: Cleanup check for stack expansion

2017-08-03T06:06:51+00:00

When hitting below a VM_GROWSDOWN vma (typically growing the stack), we check whether it's a valid stack-growing instruction and we check the distance to GPR1. This is largely open coded with lots of comments, so move it out to a helper. While at it, make store_update_sp a boolean. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman

powerpc/mm: Don't lose "major" fault indication on retry

2017-08-03T06:06:51+00:00

If the first iteration returns VM_FAULT_MAJOR but the second one doesn't, we fail to account the fault as a major fault. This fixes it and brings the code in line with x86. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman