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

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

[Sasha Levin]

From: Helge Deller <deller@gmx.de>

[ Upstream commit 6c800d7f55fcd78e17deae5ae4374d8e73482c13 ]

This reverts commit a9fe7fa7d874a536e0540469f314772c054a0323.

Leads to segfaults on 32bit kernel.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.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

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

[Helge Deller]

Hello Sascha,

please drop this patch from all your stable-series queues....
It shouldn't be backported.

Thanks,
Helge

On 5/10/22 17:43, Sasha Levin wrote:
> From: Helge Deller <deller@gmx.de>
>
> [ Upstream commit 6c800d7f55fcd78e17deae5ae4374d8e73482c13 ]
>
> This reverts commit a9fe7fa7d874a536e0540469f314772c054a0323.
>
> Leads to segfaults on 32bit kernel.
>
> Signed-off-by: Helge Deller <deller@gmx.de>
> Signed-off-by: Sasha Levin <sashal@kernel.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)

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

[Sasha Levin]

On Tue, May 10, 2022 at 05:49:31PM +0200, Helge Deller wrote:
>Hello Sascha,
>
>please drop this patch from all your stable-series queues....
>It shouldn't be backported.

I've dropped it, but... why?

-- 
Thanks,
Sasha

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

[John David Anglin]

On 2022-05-14 12:24 p.m., Sasha Levin wrote:
> On Tue, May 10, 2022 at 05:49:31PM +0200, Helge Deller wrote:
>> Hello Sascha,
>>
>> please drop this patch from all your stable-series queues....
>> It shouldn't be backported.
>
> I've dropped it, but... why?
It exposed a problem in the kernel flush code for PA 1.x machines. The patch works okay on
all PA 2.0 machines.  It also works on PA 1.x machines when flush_cache_all is used to flush
changes to memory.

Helge is investigating PA 1.x problem.

-- 
John David Anglin  dave.anglin@bell.net