[PATCH urgent] MIPS: fix micro-assembly overflow in set_except_vector

[PATCH urgent] MIPS: fix micro-assembly overflow in set_except_vector

[Florian Fainelli]

Commit 24a6d9866c5f15ba7e5b14dc17be4b6edba21d0e broke
the installation of handlers for boards which have their
handlers above a 1 << 26 address. Fix this by making sure that
jump_mask does not excess 0xfc000000 and add the missing ~ operator
to jump_mask when jumping to the handler address.

Reported-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
---
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 7693929..40d94c3 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1279,11 +1279,11 @@ void __init *set_except_vector(int n, void *addr)
 
 	exception_handlers[n] = handler;
 	if (n == 0 && cpu_has_divec) {
-		unsigned long jump_mask = ~((1 << 28) - 1);
+		unsigned long jump_mask = ~((1 << 26) - 1);
 		u32 *buf = (u32 *)(ebase + 0x200);
 		unsigned int k0 = 26;
 		if ((handler & jump_mask) == ((ebase + 0x200) & jump_mask)) {
-			uasm_i_j(&buf, handler & jump_mask);
+			uasm_i_j(&buf, handler & ~jump_mask);
 			uasm_i_nop(&buf);
 		} else {
 			UASM_i_LA(&buf, k0, handler);

Re: [PATCH urgent] MIPS: fix micro-assembly overflow in set_except_vector

[David Daney]

Florian Fainelli wrote:
> Commit 24a6d9866c5f15ba7e5b14dc17be4b6edba21d0e broke
> the installation of handlers for boards which have their
> handlers above a 1 << 26 address. Fix this by making sure that
> jump_mask does not excess 0xfc000000 and add the missing ~ operator
> to jump_mask when jumping to the handler address.
> 
> Reported-by: Maxime Bizon <mbizon@freebox.fr>
> Signed-off-by: Florian Fainelli <florian@openwrt.org>

Acked-by: David Daney <ddaney@caviumnetworks.com>

> ---
> diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
> index 7693929..40d94c3 100644
> --- a/arch/mips/kernel/traps.c
> +++ b/arch/mips/kernel/traps.c
> @@ -1279,11 +1279,11 @@ void __init *set_except_vector(int n, void *addr)
>  
>  	exception_handlers[n] = handler;
>  	if (n == 0 && cpu_has_divec) {
> -		unsigned long jump_mask = ~((1 << 28) - 1);
> +		unsigned long jump_mask = ~((1 << 26) - 1);
>  		u32 *buf = (u32 *)(ebase + 0x200);
>  		unsigned int k0 = 26;
>  		if ((handler & jump_mask) == ((ebase + 0x200) & jump_mask)) {
> -			uasm_i_j(&buf, handler & jump_mask);
> +			uasm_i_j(&buf, handler & ~jump_mask);
>  			uasm_i_nop(&buf);
>  		} else {
>  			UASM_i_LA(&buf, k0, handler);
> 
> 
> 

Re: [PATCH urgent] MIPS: fix micro-assembly overflow in set_except_vector

[Florian Fainelli]

Hi Thomas,

On Monday 01 February 2010 11:36:28 Thomas Bogendoerfer wrote:
> On Mon, Feb 01, 2010 at 10:27:37AM +0100, Florian Fainelli wrote:
> > Commit 24a6d9866c5f15ba7e5b14dc17be4b6edba21d0e broke
> > the installation of handlers for boards which have their
> > handlers above a 1 << 26 address. Fix this by making sure that
> > jump_mask does not excess 0xfc000000 and add the missing ~ operator
> 
> j can handle 28 bit jump targets (26 bit in instruction plus two 0 bits
> for 32bit aligment), so 0xf000000 was IMHO fine.

Corrected version below, thanks.
---
From: Florian Fainelli <florian@openwrt.org>
Subject: [PATCH urgent] MIPS: fix micro-assembly overflow in set_except_vector

Commit 24a6d9866c5f15ba7e5b14dc17be4b6edba21d0e broke
the installation of handlers for boards which have their
handlers above 0xf0000000. Fix this by adding the missing
~ operator to jump_mask when loading the handler target
address into buf.

Reported-by: Maxime Bizon <mbizon@freebox.fr>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
---
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 7693929..af176b8 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1283,7 +1283,7 @@ void __init *set_except_vector(int n, void *addr)
 		u32 *buf = (u32 *)(ebase + 0x200);
 		unsigned int k0 = 26;
 		if ((handler & jump_mask) == ((ebase + 0x200) & jump_mask)) {
-			uasm_i_j(&buf, handler & jump_mask);
+			uasm_i_j(&buf, handler & ~jump_mask);
 			uasm_i_nop(&buf);
 		} else {
 			UASM_i_LA(&buf, k0, handler);

Re: [PATCH urgent] MIPS: fix micro-assembly overflow in set_except_vector

[Ralf Baechle]

On Tue, Feb 02, 2010 at 10:06:35AM +0100, Florian Fainelli wrote:

> On Monday 01 February 2010 11:36:28 Thomas Bogendoerfer wrote:
> > On Mon, Feb 01, 2010 at 10:27:37AM +0100, Florian Fainelli wrote:
> > > Commit 24a6d9866c5f15ba7e5b14dc17be4b6edba21d0e broke
> > > the installation of handlers for boards which have their
> > > handlers above a 1 << 26 address. Fix this by making sure that
> > > jump_mask does not excess 0xfc000000 and add the missing ~ operator
> > 
> > j can handle 28 bit jump targets (26 bit in instruction plus two 0 bits
> > for 32bit aligment), so 0xf000000 was IMHO fine.
> 
> Corrected version below, thanks.

Folded into the existing -queue patch.

Thanks,

  Ralf