linux-kernel - [PATCH AUTOSEL 5.17 21/21] Revert "parisc: Fix patch code locking and flushing"

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Date:   Tue, 10 May 2022 11:43:40 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Helge Deller <deller@....de>, Sasha Levin <sashal@...nel.org>,
        James.Bottomley@...senPartnership.com, dave.anglin@...l.net,
        linux-parisc@...r.kernel.org
Subject: [PATCH AUTOSEL 5.17 21/21] Revert "parisc: Fix patch code locking and flushing"

From: Helge Deller <deller@....de>

[ Upstream commit 6c800d7f55fcd78e17deae5ae4374d8e73482c13 ]

This reverts commit a9fe7fa7d874a536e0540469f314772c054a0323.

Leads to segfaults on 32bit kernel.

Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/parisc/kernel/patch.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/arch/parisc/kernel/patch.c b/arch/parisc/kernel/patch.c
index e59574f65e64..80a0ab372802 100644
--- a/arch/parisc/kernel/patch.c
+++ b/arch/parisc/kernel/patch.c
@@ -40,7 +40,10 @@ static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags,
 
 	*need_unmap = 1;
 	set_fixmap(fixmap, page_to_phys(page));
-	raw_spin_lock_irqsave(&patch_lock, *flags);
+	if (flags)
+		raw_spin_lock_irqsave(&patch_lock, *flags);
+	else
+		__acquire(&patch_lock);
 
 	return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
 }
@@ -49,7 +52,10 @@ static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
 {
 	clear_fixmap(fixmap);
 
-	raw_spin_unlock_irqrestore(&patch_lock, *flags);
+	if (flags)
+		raw_spin_unlock_irqrestore(&patch_lock, *flags);
+	else
+		__release(&patch_lock);
 }
 
 void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
@@ -61,9 +67,8 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
 	int mapped;
 
 	/* Make sure we don't have any aliases in cache */
-	flush_kernel_dcache_range_asm(start, end);
-	flush_kernel_icache_range_asm(start, end);
-	flush_tlb_kernel_range(start, end);
+	flush_kernel_vmap_range(addr, len);
+	flush_icache_range(start, end);
 
 	p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags, &mapped);
 
@@ -76,10 +81,8 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
 			 * We're crossing a page boundary, so
 			 * need to remap
 			 */
-			flush_kernel_dcache_range_asm((unsigned long)fixmap,
-						      (unsigned long)p);
-			flush_tlb_kernel_range((unsigned long)fixmap,
-					       (unsigned long)p);
+			flush_kernel_vmap_range((void *)fixmap,
+						(p-fixmap) * sizeof(*p));
 			if (mapped)
 				patch_unmap(FIX_TEXT_POKE0, &flags);
 			p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags,
@@ -87,10 +90,10 @@ void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
 		}
 	}
 
-	flush_kernel_dcache_range_asm((unsigned long)fixmap, (unsigned long)p);
-	flush_tlb_kernel_range((unsigned long)fixmap, (unsigned long)p);
+	flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p));
 	if (mapped)
 		patch_unmap(FIX_TEXT_POKE0, &flags);
+	flush_icache_range(start, end);
 }
 
 void __kprobes __patch_text(void *addr, u32 insn)
-- 
2.35.1