kernel.git/arch/powerpc/include/asm/interrupt.h, branch linux-5.13.y

powerpc/interrupt: Fix OOPS by not calling do_IRQ() from timer_interrupt()

2021-08-18T07:07:04Z

commit 98694166c27d473c36b434bd3572934c2f2a16ab upstream. An interrupt handler shall not be called from another interrupt handler otherwise this leads to problems like the following: Kernel attempted to write user page (afd4fa84) - exploit attempt? (uid: 1000) ------------[ cut here ]------------ Bug: Write fault blocked by KUAP! WARNING: CPU: 0 PID: 1617 at arch/powerpc/mm/fault.c:230 do_page_fault+0x484/0x720 Modules linked in: CPU: 0 PID: 1617 Comm: sshd Tainted: G W 5.13.0-pmac-00010-g8393422eb77 #7 NIP: c001b77c LR: c001b77c CTR: 00000000 REGS: cb9e5bc0 TRAP: 0700 Tainted: G W (5.13.0-pmac-00010-g8393422eb77) MSR: 00021032 CR: 24942424 XER: 00000000 GPR00: c001b77c cb9e5c80 c1582c00 00000021 3ffffbff 085b0000 00000027 c8eb644c GPR08: 00000023 00000000 00000000 00000000 24942424 0063f8c8 00000000 000186a0 GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 c07640c4 cb9e5e98 cb9e5e90 GPR24: 00000040 afd4fa96 00000040 02000000 c1fda6c0 afd4fa84 00000300 cb9e5cc0 NIP [c001b77c] do_page_fault+0x484/0x720 LR [c001b77c] do_page_fault+0x484/0x720 Call Trace: [cb9e5c80] [c001b77c] do_page_fault+0x484/0x720 (unreliable) [cb9e5cb0] [c000424c] DataAccess_virt+0xd4/0xe4 --- interrupt: 300 at __copy_tofrom_user+0x110/0x20c NIP: c001f9b4 LR: c03250a0 CTR: 00000004 REGS: cb9e5cc0 TRAP: 0300 Tainted: G W (5.13.0-pmac-00010-g8393422eb77) MSR: 00009032 CR: 48028468 XER: 20000000 DAR: afd4fa84 DSISR: 0a000000 GPR00: 20726f6f cb9e5d80 c1582c00 00000004 cb9e5e3a 00000016 afd4fa80 00000000 GPR08: 3835202d 72777872 2d78722d 00000004 28028464 0063f8c8 00000000 000186a0 GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 c07640c4 cb9e5e98 cb9e5e90 GPR24: 00000040 afd4fa96 00000040 cb9e5e0c 00000daa a0000000 cb9e5e98 afd4fa56 NIP [c001f9b4] __copy_tofrom_user+0x110/0x20c LR [c03250a0] _copy_to_iter+0x144/0x990 --- interrupt: 300 [cb9e5d80] [c03e89c0] n_tty_read+0xa4/0x598 (unreliable) [cb9e5df0] [c03e2a0c] tty_read+0xdc/0x2b4 [cb9e5e80] [c0156bf8] vfs_read+0x274/0x340 [cb9e5f00] [c01571ac] ksys_read+0x70/0x118 [cb9e5f30] [c0016048] ret_from_syscall+0x0/0x28 --- interrupt: c00 at 0xa7855c88 NIP: a7855c88 LR: a7855c5c CTR: 00000000 REGS: cb9e5f40 TRAP: 0c00 Tainted: G W (5.13.0-pmac-00010-g8393422eb77) MSR: 0000d032 CR: 2402446c XER: 00000000 GPR00: 00000003 afd4ec70 a72137d0 0000000b afd4ecac 00004000 0065a990 00000800 GPR08: 00000000 a7947930 00000000 00000004 c15831b0 0063f8c8 00000000 000186a0 GPR16: afd52dd4 afd52dd0 afd52dcc afd52dc8 0065a990 0065a9e0 00000001 0065fac0 GPR24: 00000000 00000089 00664050 00000000 00668e30 a720c8dc a7943ff4 0065f9b0 NIP [a7855c88] 0xa7855c88 LR [a7855c5c] 0xa7855c5c --- interrupt: c00 Instruction dump: 3884aa88 38630178 48076861 807f0080 48042e45 2f830000 419e0148 3c80c079 3c60c076 38841be4 386301c0 4801f705 <0fe00000> 3860000b 4bfffe30 3c80c06b ---[ end trace fd69b91a8046c2e5 ]--- Here the problem is that by re-enterring an exception handler, kuap_save_and_lock() is called a second time with this time KUAP access locked, leading to regs->kuap being overwritten hence KUAP not being unlocked at exception exit as expected. Do not call do_IRQ() from timer_interrupt() directly. Instead, redefine do_IRQ() as a standard function named __do_IRQ(), and call it from both do_IRQ() and time_interrupt() handlers. Fixes: 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers") Cc: stable@vger.kernel.org # v5.12+ Reported-by: Stan Johnson Signed-off-by: Christophe Leroy Reviewed-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/c17d234f4927d39a1d7100864a8e1145323d33a0.1628611927.git.christophe.leroy@csgroup.eu Signed-off-by: Greg Kroah-Hartman

powerpc/64s/interrupt: preserve regs->softe for NMI interrupts

2021-07-14T15:07:46Z

[ Upstream commit 1b0482229c302a3c6afd00d6b3bf0169cf279b44 ] If an NMI interrupt hits in an implicit soft-masked region, regs->softe is modified to reflect that. This may not be necessary for correctness at the moment, but it is less surprising and it's unhelpful when debugging or adding checks. Make sure this is changed back to how it was found before returning. Fixes: 4ec5feec1ad0 ("powerpc/64s: Make NMI record implicitly soft-masked code as irqs disabled") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210630074621.2109197-6-npiggin@gmail.com Signed-off-by: Sasha Levin

powerpc/64s: Make NMI record implicitly soft-masked code as irqs disabled

2021-05-14T07:28:52Z

scv support introduced the notion of code that implicitly soft-masks irqs due to the instruction addresses. This is required because scv enters the kernel with MSR[EE]=1. If a NMI (including soft-NMI) interrupt hits when we are implicitly soft-masked then its regs->softe does not reflect this because it is derived from the explicit soft mask state (paca->irq_soft_mask). This makes arch_irq_disabled_regs(regs) return false. This can trigger a warning in the soft-NMI watchdog code (shown below). Fix it by having NMI interrupts set regs->softe to disabled in case of interrupting an implicit soft-masked region. ------------[ cut here ]------------ WARNING: CPU: 41 PID: 1103 at arch/powerpc/kernel/watchdog.c:259 soft_nmi_interrupt+0x3e4/0x5f0 CPU: 41 PID: 1103 Comm: (spawn) Not tainted NIP: c000000000039534 LR: c000000000039234 CTR: c000000000009a00 REGS: c000007fffbcf940 TRAP: 0700 Not tainted MSR: 9000000000021033 CR: 22042482 XER: 200400ad CFAR: c000000000039260 IRQMASK: 3 GPR00: c000000000039204 c000007fffbcfbe0 c000000001d6c300 0000000000000003 GPR04: 00007ffffa45d078 0000000000000000 0000000000000008 0000000000000020 GPR08: 0000007ffd4e0000 0000000000000000 c000007ffffceb00 7265677368657265 GPR12: 9000000000009033 c000007ffffceb00 00000f7075bf4480 000000000000002a GPR16: 00000f705745a528 00007ffffa45ddd8 00000f70574d0008 0000000000000000 GPR20: 00000f7075c58d70 00000f7057459c38 0000000000000001 0000000000000040 GPR24: 0000000000000000 0000000000000029 c000000001dae058 0000000000000029 GPR28: 0000000000000000 0000000000000800 0000000000000009 c000007fffbcfd60 NIP [c000000000039534] soft_nmi_interrupt+0x3e4/0x5f0 LR [c000000000039234] soft_nmi_interrupt+0xe4/0x5f0 Call Trace: [c000007fffbcfbe0] [c000000000039204] soft_nmi_interrupt+0xb4/0x5f0 (unreliable) [c000007fffbcfcf0] [c00000000000c0e8] soft_nmi_common+0x138/0x1c4 --- interrupt: 900 at end_real_trampolines+0x0/0x1000 NIP: c000000000003000 LR: 00007ca426adb03c CTR: 900000000280f033 REGS: c000007fffbcfd60 TRAP: 0900 MSR: 9000000000009033 CR: 44042482 XER: 200400ad CFAR: 00007ca426946020 IRQMASK: 0 GPR00: 00000000000000ad 00007ffffa45d050 00007ca426b07f00 0000000000000035 GPR04: 00007ffffa45d078 0000000000000000 0000000000000008 0000000000000020 GPR08: 0000000000000000 0000000000100000 0000000010000000 00007ffffa45d110 GPR12: 0000000000000001 00007ca426d4e680 00000f7075bf4480 000000000000002a GPR16: 00000f705745a528 00007ffffa45ddd8 00000f70574d0008 0000000000000000 GPR20: 00000f7075c58d70 00000f7057459c38 0000000000000001 0000000000000040 GPR24: 0000000000000000 00000f7057473f68 0000000000000003 000000000000041b GPR28: 00007ffffa45d4c4 0000000000000035 0000000000000000 00000f7057473f68 NIP [c000000000003000] end_real_trampolines+0x0/0x1000 LR [00007ca426adb03c] 0x7ca426adb03c --- interrupt: 900 Instruction dump: 60000000 60000000 60420000 38600001 482b3ae5 60000000 e93f0138 a36d0008 7daa6b78 71290001 7f7907b4 4082fd34 <0fe00000> 4bfffd2c 60420000 ea6100a8 ---[ end trace dc75f67d819779da ]--- Fixes: 118178e62e2e ("powerpc: move NMI entry/exit code into wrapper") Reported-by: Cédric Le Goater Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210503111708.758261-1-npiggin@gmail.com

powerpc/interrupts: Fix kuep_unlock() call

2021-05-12T01:07:37Z

Same as kuap_user_restore(), kuep_unlock() has to be called when really returning to user, that is in interrupt_exit_user_prepare(), not in interrupt_exit_prepare(). Fixes: b5efec00b671 ("powerpc/32s: Move KUEP locking/unlocking in C") Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/b831e54a2579db24fbef836ed415588ce2b3e825.1620312573.git.christophe.leroy@csgroup.eu

powerpc/irq: Enhance readability of trap types

2021-04-21T12:52:32Z

This patch makes use of trap types in irq.c Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/f7f8c9f98c33eaea316755c7fef150d1d77e047d.1618847273.git.christophe.leroy@csgroup.eu

powerpc/32s: Enhance readability of trap types

2021-04-21T12:52:31Z

This patch makes use of trap types in head_book3s_32.S Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/bd80ace67757f489fc4ecdb76dd1a71511daba94.1618847273.git.christophe.leroy@csgroup.eu

powerpc/8xx: Enhance readability of trap types

2021-04-21T12:52:31Z

This patch makes use of trap types in head_8xx.S Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/e1147287bf6f2fb0693048fe8db0298c7870e419.1618847273.git.christophe.leroy@csgroup.eu

powerpc/traps: Enhance readability for trap types

2021-04-17T12:20:19Z

Define macros to list ppc interrupt types in interttupt.h, replace the reference of the trap hex values with these macros. Referred the hex numbers in arch/powerpc/kernel/exceptions-64e.S, arch/powerpc/kernel/exceptions-64s.S, arch/powerpc/kernel/head_*.S, arch/powerpc/kernel/head_booke.h and arch/powerpc/include/asm/kvm_asm.h. Signed-off-by: Xiongwei Song [mpe: Resolve conflicts in nmi_disables_ftrace(), fix 40x build] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1618398033-13025-1-git-send-email-sxwjean@me.com

powerpc: clean up do_page_fault

2021-04-14T13:04:44Z

search_exception_tables + __bad_page_fault can be substituted with bad_page_fault, do_page_fault no longer needs to return a value to asm for any sub-architecture, and __bad_page_fault can be static. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210316104206.407354-10-npiggin@gmail.com

powerpc/64e/interrupt: Use new interrupt context tracking scheme

2021-04-14T13:04:43Z

With the new interrupt exit code, context tracking can be managed more precisely, so remove the last of the 64e workarounds and switch to the new context tracking code already used by 64s. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20210316104206.407354-8-npiggin@gmail.com