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From 1ec2f2c05b2ab845d068bff29bd32dbfc6a6ad4c Mon Sep 17 00:00:00 2001 |
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From: Mark Rutland <mark.rutland@arm.com> |
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Date: Mon, 30 Nov 2020 11:59:47 +0000 |
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Subject: [PATCH 130/150] arm64: ptrace: prepare for EL1 irq/rcu tracking |
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|
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Exceptions from EL1 may be taken when RCU isn't watching (e.g. in idle |
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sequences), or when the lockdep hardirqs transiently out-of-sync with |
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the hardware state (e.g. in the middle of local_irq_enable()). To |
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correctly handle these cases, we'll need to save/restore this state |
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across some exceptions taken from EL1. |
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|
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A series of subsequent patches will update EL1 exception handlers to |
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handle this. In preparation for this, and to avoid dependencies between |
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those patches, this patch adds two new fields to struct pt_regs so that |
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exception handlers can track this state. |
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|
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Note that this is placed in pt_regs as some entry/exit sequences such as |
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el1_irq are invoked from assembly, which makes it very difficult to add |
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a separate structure as with the irqentry_state used by x86. We can |
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separate this once more of the exception logic is moved to C. While the |
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fields only need to be bool, they are both made u64 to keep pt_regs |
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16-byte aligned. |
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|
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There should be no functional change as a result of this patch. |
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|
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Signed-off-by: Mark Rutland <mark.rutland@arm.com> |
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Cc: Catalin Marinas <catalin.marinas@arm.com> |
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Cc: James Morse <james.morse@arm.com> |
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Cc: Will Deacon <will@kernel.org> |
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Link: https://lore.kernel.org/r/20201130115950.22492-9-mark.rutland@arm.com |
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Signed-off-by: Will Deacon <will@kernel.org> |
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--- |
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arch/arm64/include/asm/ptrace.h | 4 ++++ |
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1 file changed, 4 insertions(+) |
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|
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diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h |
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index 997cf8c8cd52..28c85b87b8cd 100644 |
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--- a/arch/arm64/include/asm/ptrace.h |
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+++ b/arch/arm64/include/asm/ptrace.h |
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@@ -193,6 +193,10 @@ struct pt_regs { |
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/* Only valid when ARM64_HAS_IRQ_PRIO_MASKING is enabled. */ |
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u64 pmr_save; |
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u64 stackframe[2]; |
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+ |
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+ /* Only valid for some EL1 exceptions. */ |
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+ u64 lockdep_hardirqs; |
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+ u64 exit_rcu; |
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}; |
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|
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static inline bool in_syscall(struct pt_regs const *regs) |
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-- |
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2.29.2 |
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