From: Christophe Leroy <christophe.leroy@csgroup.eu> To: Benjamin Herrenschmidt <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au> Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v2 5/5] powerpc/mm: Don't WARN() on KUAP fault Date: Mon, 16 Nov 2020 15:53:17 +0000 (UTC) [thread overview] Message-ID: <cc9129bdda1dbc2f0a09cf45fece7d0b0e690784.1605541983.git.christophe.leroy@csgroup.eu> (raw) In-Reply-To: <40ae19c2bf013e3815a6ae0d6016963fdb0f51b7.1605541983.git.christophe.leroy@csgroup.eu> The WARN() in do_page_fault() is useless the problem is not in do_page_fault() but on the place which generated the DSI exception. We already have a dump from the Oops, no need of a WARN() in addition The warning emitted by bad_kernel_fault() is good enough. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- v2: New (Partly taken from patch "powerpc/mm: Kill the task on KUAP fault") --- arch/powerpc/include/asm/book3s/32/kup.h | 6 +----- arch/powerpc/include/asm/book3s/64/kup-radix.h | 7 ++++--- arch/powerpc/include/asm/nohash/32/kup-8xx.h | 3 +-- 3 files changed, 6 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 32fd4452e960..a0117a9d5b06 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -183,11 +183,7 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) unsigned long begin = regs->kuap & 0xf0000000; unsigned long end = regs->kuap << 28; - if (!is_write) - return false; - - return WARN(address < begin || address >= end, - "Bug: write fault blocked by segment registers !"); + return is_write && (address < begin || address >= end); } #endif /* CONFIG_PPC_KUAP */ diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h index 3ee1ec60be84..8bdf559a4b32 100644 --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h @@ -161,9 +161,10 @@ static inline void restore_user_access(unsigned long flags) static inline bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) { - return WARN(mmu_has_feature(MMU_FTR_RADIX_KUAP) && - (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)), - "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read"); + if (!mmu_has_feature(MMU_FTR_RADIX_KUAP)) + return false; + + return !!(regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)); } #else /* CONFIG_PPC_KUAP */ static inline void kuap_restore_amr(struct pt_regs *regs, unsigned long amr) diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h index 567cdc557402..17a4a616436f 100644 --- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h @@ -63,8 +63,7 @@ static inline void restore_user_access(unsigned long flags) static inline bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) { - return WARN(!((regs->kuap ^ MD_APG_KUAP) & 0xff000000), - "Bug: fault blocked by AP register !"); + return !((regs->kuap ^ MD_APG_KUAP) & 0xff000000); } #endif /* !__ASSEMBLY__ */ -- 2.25.0
WARNING: multiple messages have this Message-ID (diff)
From: Christophe Leroy <christophe.leroy@csgroup.eu> To: Benjamin Herrenschmidt <benh@kernel.crashing.org>, Paul Mackerras <paulus@samba.org>, Michael Ellerman <mpe@ellerman.id.au> Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 5/5] powerpc/mm: Don't WARN() on KUAP fault Date: Mon, 16 Nov 2020 15:53:17 +0000 (UTC) [thread overview] Message-ID: <cc9129bdda1dbc2f0a09cf45fece7d0b0e690784.1605541983.git.christophe.leroy@csgroup.eu> (raw) In-Reply-To: <40ae19c2bf013e3815a6ae0d6016963fdb0f51b7.1605541983.git.christophe.leroy@csgroup.eu> The WARN() in do_page_fault() is useless the problem is not in do_page_fault() but on the place which generated the DSI exception. We already have a dump from the Oops, no need of a WARN() in addition The warning emitted by bad_kernel_fault() is good enough. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- v2: New (Partly taken from patch "powerpc/mm: Kill the task on KUAP fault") --- arch/powerpc/include/asm/book3s/32/kup.h | 6 +----- arch/powerpc/include/asm/book3s/64/kup-radix.h | 7 ++++--- arch/powerpc/include/asm/nohash/32/kup-8xx.h | 3 +-- 3 files changed, 6 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 32fd4452e960..a0117a9d5b06 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -183,11 +183,7 @@ bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) unsigned long begin = regs->kuap & 0xf0000000; unsigned long end = regs->kuap << 28; - if (!is_write) - return false; - - return WARN(address < begin || address >= end, - "Bug: write fault blocked by segment registers !"); + return is_write && (address < begin || address >= end); } #endif /* CONFIG_PPC_KUAP */ diff --git a/arch/powerpc/include/asm/book3s/64/kup-radix.h b/arch/powerpc/include/asm/book3s/64/kup-radix.h index 3ee1ec60be84..8bdf559a4b32 100644 --- a/arch/powerpc/include/asm/book3s/64/kup-radix.h +++ b/arch/powerpc/include/asm/book3s/64/kup-radix.h @@ -161,9 +161,10 @@ static inline void restore_user_access(unsigned long flags) static inline bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) { - return WARN(mmu_has_feature(MMU_FTR_RADIX_KUAP) && - (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)), - "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read"); + if (!mmu_has_feature(MMU_FTR_RADIX_KUAP)) + return false; + + return !!(regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)); } #else /* CONFIG_PPC_KUAP */ static inline void kuap_restore_amr(struct pt_regs *regs, unsigned long amr) diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h index 567cdc557402..17a4a616436f 100644 --- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h @@ -63,8 +63,7 @@ static inline void restore_user_access(unsigned long flags) static inline bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) { - return WARN(!((regs->kuap ^ MD_APG_KUAP) & 0xff000000), - "Bug: fault blocked by AP register !"); + return !((regs->kuap ^ MD_APG_KUAP) & 0xff000000); } #endif /* !__ASSEMBLY__ */ -- 2.25.0
next prev parent reply other threads:[~2020-11-16 15:53 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-16 15:53 [PATCH v2 1/5] powerpc/mm: sanity_check_fault() should work for all, not only BOOK3S Christophe Leroy 2020-11-16 15:53 ` Christophe Leroy 2020-11-16 15:53 ` [PATCH v2 2/5] powerpc/fault: Unnest definition of page_fault_is_write() and page_fault_is_bad() Christophe Leroy 2020-11-16 15:53 ` Christophe Leroy 2020-11-16 15:53 ` [PATCH v2 3/5] powerpc/fault: Avoid heavy search_exception_tables() verification Christophe Leroy 2020-11-16 15:53 ` Christophe Leroy 2020-11-16 15:53 ` [PATCH v2 4/5] powerpc/fault: Perform exception fixup in do_page_fault() Christophe Leroy 2020-11-16 15:53 ` Christophe Leroy 2020-11-16 15:53 ` Christophe Leroy [this message] 2020-11-16 15:53 ` [PATCH v2 5/5] powerpc/mm: Don't WARN() on KUAP fault Christophe Leroy
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