Re: [PATCH v3 08/12] arm64: Move esr_comment() to <asm/esr.h>

From: Will Deacon <will@kernel.org>
To: "Pierre-Clément Tosi" <ptosi@google.com>
Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Vincent Donnefort <vdonnefort@google.com>
Subject: Re: [PATCH v3 08/12] arm64: Move esr_comment() to <asm/esr.h>
Date: Mon, 13 May 2024 15:57:02 +0100	[thread overview]
Message-ID: <20240513145702.GG28749@willie-the-truck> (raw)
In-Reply-To: <20240510112645.3625702-9-ptosi@google.com>

On Fri, May 10, 2024 at 12:26:37PM +0100, Pierre-Clément Tosi wrote:
> As it is already defined twice and is about to be needed for kCFI error
> detection, move esr_comment() to a header for re-use, with a clearer
> name.

esr_comment() is defined twice? I only see one macro definition, but yes,
it's open-coded in nvhe_hyp_panic_handler too.

> Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
> ---
>  arch/arm64/include/asm/esr.h       | 5 +++++
>  arch/arm64/kernel/debug-monitors.c | 4 +---
>  arch/arm64/kernel/traps.c          | 8 +++-----
>  arch/arm64/kvm/handle_exit.c       | 2 +-
>  4 files changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
> index 81606bf7d5ac..2bcf216be376 100644
> --- a/arch/arm64/include/asm/esr.h
> +++ b/arch/arm64/include/asm/esr.h
> @@ -379,6 +379,11 @@
>  #ifndef __ASSEMBLY__
>  #include <asm/types.h>
>  
> +static inline unsigned long esr_brk_comment(unsigned long esr)
> +{
> +	return esr & ESR_ELx_BRK64_ISS_COMMENT_MASK;
> +}
> +
>  static inline bool esr_is_data_abort(unsigned long esr)
>  {
>  	const unsigned long ec = ESR_ELx_EC(esr);
> diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
> index 64f2ecbdfe5c..024a7b245056 100644
> --- a/arch/arm64/kernel/debug-monitors.c
> +++ b/arch/arm64/kernel/debug-monitors.c
> @@ -312,9 +312,7 @@ static int call_break_hook(struct pt_regs *regs, unsigned long esr)
>  	 * entirely not preemptible, and we can use rcu list safely here.
>  	 */
>  	list_for_each_entry_rcu(hook, list, node) {
> -		unsigned long comment = esr & ESR_ELx_BRK64_ISS_COMMENT_MASK;
> -
> -		if ((comment & ~hook->mask) == hook->imm)
> +		if ((esr_brk_comment(esr) & ~hook->mask) == hook->imm)
>  			fn = hook->fn;
>  	}
>  
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 215e6d7f2df8..2652247032ae 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -1105,8 +1105,6 @@ static struct break_hook ubsan_break_hook = {
>  };
>  #endif
>  
> -#define esr_comment(esr) ((esr) & ESR_ELx_BRK64_ISS_COMMENT_MASK)
> -
>  /*
>   * Initial handler for AArch64 BRK exceptions
>   * This handler only used until debug_traps_init().
> @@ -1115,15 +1113,15 @@ int __init early_brk64(unsigned long addr, unsigned long esr,
>  		struct pt_regs *regs)
>  {
>  #ifdef CONFIG_CFI_CLANG
> -	if ((esr_comment(esr) & ~CFI_BRK_IMM_MASK) == CFI_BRK_IMM_BASE)
> +	if ((esr_brk_comment(esr) & ~CFI_BRK_IMM_MASK) == CFI_BRK_IMM_BASE)
>  		return cfi_handler(regs, esr) != DBG_HOOK_HANDLED;
>  #endif
>  #ifdef CONFIG_KASAN_SW_TAGS
> -	if ((esr_comment(esr) & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
> +	if ((esr_brk_comment(esr) & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
>  		return kasan_handler(regs, esr) != DBG_HOOK_HANDLED;
>  #endif
>  #ifdef CONFIG_UBSAN_TRAP
> -	if ((esr_comment(esr) & ~UBSAN_BRK_MASK) == UBSAN_BRK_IMM)
> +	if ((esr_brk_comment(esr) & ~UBSAN_BRK_MASK) == UBSAN_BRK_IMM)
>  		return ubsan_handler(regs, esr) != DBG_HOOK_HANDLED;
>  #endif
>  	return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 617ae6dea5d5..0bcafb3179d6 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -395,7 +395,7 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
>  	if (mode != PSR_MODE_EL2t && mode != PSR_MODE_EL2h) {
>  		kvm_err("Invalid host exception to nVHE hyp!\n");
>  	} else if (ESR_ELx_EC(esr) == ESR_ELx_EC_BRK64 &&
> -		   (esr & ESR_ELx_BRK64_ISS_COMMENT_MASK) == BUG_BRK_IMM) {
> +		   esr_brk_comment(esr) == BUG_BRK_IMM) {
>  		const char *file = NULL;
>  		unsigned int line = 0;

With the commit message tweaked:

Acked-by: Will Deacon <will@kernel.org>

Will

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