lwn.git/arch/powerpc/lib/feature-fixups.c, branch docs-6.9

powerpc/features: Add capability to update mmu features later

2023-08-02T12:22:17+00:00

On powerpc32, features fixup is performed very early and that's too early to read the cmdline and take into account 'nosmap' parameter. On the other hand, no userspace access is performed that early and KUAP feature fixup can be performed later. Add a function to update mmu features. The function is passed a mask with the features that can be updated. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://msgid.link/31b27ee2c9d338f4f82cd8cd69d6bff979495290.1689091022.git.christophe.leroy@csgroup.eu

powerpc/feature-fixups: Do not patch init section after init

2022-12-02T10:59:57+00:00

Once init section is freed, attempting to patch init code ends up in the weed. Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections") protected patch_instruction() against that, but it is the responsibility of the caller to ensure that the patched memory is valid. In the same spirit as jump_label with its jump_label_can_update() function, add is_fixup_addr_valid() function to skip patching on freed init section. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/8e9311fc1b057e4e6a2a3a0701ebcc74b787affe.1669969781.git.christophe.leroy@csgroup.eu

powerpc/feature-fixups: Refactor other fixups patching

2022-12-02T10:59:56+00:00

Several fonctions have the same loop for patching instructions. Introduce function do_patch_fixups() to refactor those loops. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/58ab36949c18f94d466fc98d6c085783b0cd474f.1669969781.git.christophe.leroy@csgroup.eu

powerpc/feature-fixups: Refactor entry fixups patching

2022-12-02T10:59:56+00:00

Several fonctions have the same loop for patching instructions. Introduce function do_patch_entry_fixups() to refactor those loops. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/79eeff7b20a98f7136da5f79b1f7c436928f27f3.1669969781.git.christophe.leroy@csgroup.eu

powerpc: Remove CONFIG_PPC_FSL_BOOK3E

2022-09-26T13:00:13+00:00

CONFIG_PPC_FSL_BOOK3E is redundant with CONFIG_PPC_E500. Remove it. And rename five files accordingly. Signed-off-by: Christophe Leroy [mpe: Rename include guards to match new file names] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/795cb93b88c9a0279289712e674f39e3b108a1b4.1663606876.git.christophe.leroy@csgroup.eu

powerpc/inst: Remove PPC_INST_BRANCH

2022-05-22T05:58:27+00:00

Convert last users of PPC_INST_BRANCH to PPC_RAW_BRANCH() And remove PPC_INST_BRANCH. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/fa8807108a2ef2287a2c9651d6e1ff7c051923d9.1652074503.git.christophe.leroy@csgroup.eu

powerpc/lib: Add __init attribute to eligible functions

2021-12-23T11:33:10+00:00

Some functions defined in 'arch/powerpc/lib' are deserving of an `__init` macro attribute. These functions are only called by other initialization functions and therefore should inherit the attribute. Also, change function declarations in header files to include `__init`. Signed-off-by: Nick Child Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211216220035.605465-3-nick.child@ibm.com

powerpc/inst: Define ppc_inst_t

2021-12-09T11:41:21+00:00

In order to stop using 'struct ppc_inst' on PPC32, define a ppc_inst_t typedef. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/fe5baa2c66fea9db05a8b300b3e8d2880a42596c.1638208156.git.christophe.leroy@csgroup.eu

powerpc/security: Use a mutex for interrupt exit code patching

2021-10-28T06:23:58+00:00

The mitigation-patching.sh script in the powerpc selftests toggles all mitigations on and off simultaneously, revealing that rfi_flush and stf_barrier cannot safely operate at the same time due to races in updating the static key. On some systems, the static key code throws a warning and the kernel remains functional. On others, the kernel will hang or crash. Fix this by slapping on a mutex. Fixes: 13799748b957 ("powerpc/64: use interrupt restart table to speed up return from interrupt") Cc: stable@vger.kernel.org # v5.14+ Signed-off-by: Russell Currey Acked-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20211027072410.40950-1-ruscur@russell.cc

powerpc/64: use interrupt restart table to speed up return from interrupt

2021-06-24T14:06:56+00:00

Use the restart table facility to return from interrupt or system calls without disabling MSR[EE] or MSR[RI]. Interrupt return asm is put into the low soft-masked region, to prevent interrupts being processed here, although they are still taken as masked interrupts which causes SRRs to be clobbered, and a pending soft-masked interrupt to require replaying. The return code uses restart table regions to redirct to a fixup handler rather than continue with the exit, if such an interrupt happens. In this case the interrupt return is redirected to a fixup handler which reloads r1 for the interrupt stack and reloads registers and sets state up to replay the soft-masked interrupt and try the exit again. Some types of security exit fallback flushes and barriers are currently unable to cope with reentrant interrupts, e.g., because they store some state in the scratch SPR which would be clobbered even by masked interrupts. For now the interrupts-enabled exits are disabled when these flushes are used. Signed-off-by: Nicholas Piggin [mpe: Guard unused exit_must_hard_disable() as reported by lkp] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210617155116.2167984-13-npiggin@gmail.com