Re: [PATCH] arm64: mm: Use asid2idx() and asid feature macro for cleanup
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2021-12-07 10:50:48
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On Tue, Dec 07, 2021 at 10:21:26AM +0800, Yunfeng Ye wrote:
On 2021/12/7 0:23, Catalin Marinas wrote:quoted
On Thu, Oct 28, 2021 at 08:27:23PM +0800, Yunfeng Ye wrote:quoted
@@ -162,7 +162,7 @@ static u64 new_context(struct mm_struct *mm) u64 generation = atomic64_read(&asid_generation); if (asid != 0) { - u64 newasid = generation | (asid & ~ASID_MASK); + u64 newasid = generation | asid2idx(asid); /* * If our current ASID was active during a rollover, we@@ -306,7 +306,7 @@ unsigned long arm64_mm_context_get(struct mm_struct *mm) out_unlock: raw_spin_unlock_irqrestore(&cpu_asid_lock, flags); - asid &= ~ASID_MASK; + asid = asid2idx(asid);While functionally the code is the same, I don't think this was the intention of asid2idx(). It's meant to provide an index into asid_map, while the ASID_MASK lines isolate the asid number and add a new generation to it.The commit 0c8ea531b774 ("arm64: mm: Allocate ASIDs in pairs") introduce the asid2idx and idx2asid macro, but these macros is not really useful after the commit f88f42f853a8 ("arm64: context: Free up kernel ASIDs if KPTI is not in use"). I think "(asid & ~ASID_MASK)" can be instead by a macro, it is the same code with asid2idx(). Can it be renamed? (eg, ctxid2asid)
Yes, that would work. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel