From 1ec2f2c05b2ab845d068bff29bd32dbfc6a6ad4c Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 30 Nov 2020 11:59:47 +0000 Subject: [PATCH] arm64: ptrace: prepare for EL1 irq/rcu tracking Exceptions from EL1 may be taken when RCU isn't watching (e.g. in idle sequences), or when the lockdep hardirqs transiently out-of-sync with the hardware state (e.g. in the middle of local_irq_enable()). To correctly handle these cases, we'll need to save/restore this state across some exceptions taken from EL1. A series of subsequent patches will update EL1 exception handlers to handle this. In preparation for this, and to avoid dependencies between those patches, this patch adds two new fields to struct pt_regs so that exception handlers can track this state. Note that this is placed in pt_regs as some entry/exit sequences such as el1_irq are invoked from assembly, which makes it very difficult to add a separate structure as with the irqentry_state used by x86. We can separate this once more of the exception logic is moved to C. While the fields only need to be bool, they are both made u64 to keep pt_regs 16-byte aligned. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: James Morse Cc: Will Deacon Link: https://lore.kernel.org/r/20201130115950.22492-9-mark.rutland@arm.com Signed-off-by: Will Deacon --- arch/arm64/include/asm/ptrace.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h index 997cf8c8cd52..28c85b87b8cd 100644 --- a/arch/arm64/include/asm/ptrace.h +++ b/arch/arm64/include/asm/ptrace.h @@ -193,6 +193,10 @@ struct pt_regs { /* Only valid when ARM64_HAS_IRQ_PRIO_MASKING is enabled. */ u64 pmr_save; u64 stackframe[2]; + + /* Only valid for some EL1 exceptions. */ + u64 lockdep_hardirqs; + u64 exit_rcu; }; static inline bool in_syscall(struct pt_regs const *regs) -- 2.34.1