arm: fix exception vectors
PATCH 1/1 arm: fix exception vectors
After relocation, exception vectors still point to the old code (not relocated). This patch fixes them.
--- arch/arm/lib/relocate.S | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
arch/arm/lib/relocate.S +15 -0
@@ -76,6 +76,21 @@ copy_loop: blo copy_loop /* + * fix exception vectors + */ + ldr r2, =_undefined_instruction + ldr r3, =_fiq + add r2, r2, r4 + add r3, r3, r4 +fix_exceptions: + ldr r0, [r2] + add r0, r0, r4 + str r0, [r2] + cmp r2,r3 + add r2, #4 + blo fix_exceptions + + /* * fix .rel.dyn relocations */ ldr r2, =__rel_dyn_start /* r2 <- SRC &__rel_dyn_start */
Signature · 1 line
1.7.10.4
PATCH 1/1 arm: fix exception vectors
Hello Luca,
Quoted 37 lines · Luca Ellero
After relocation, exception vectors still point to the old code (not relocated). This patch fixes them.
Signed-off-by Luca Ellero <[email protected]>--- arch/arm/lib/relocate.S | 15 +++++++++++++++ 1 file changed, 15 insertions(+)arch/arm/lib/relocate.S +15
-0@@ -76,6 +76,21 @@ copy_loop: blo copy_loop /* + * fix exception vectors + */ + ldr r2, =_undefined_instruction + ldr r3, =_fiq + add r2, r2, r4 + add r3, r3, r4 +fix_exceptions: + ldr r0, [r2] + add r0, r0, r4 + str r0, [r2] + cmp r2,r3 + add r2, #4 + blo fix_exceptions + + /* * fix .rel.dyn relocations */ ldr r2, =__rel_dyn_start /* r2 <- SRC &__rel_dyn_start */Signature · 1 line
1.7.10.4
There is already a mechanism to relocate vectors (do a git grep for 'relocate_vectors' which takes into account various ISA and SoC cases.
Can you describe the use case which you are encountering?
Amicalement,
Signature · 1 line
Albert.
PATCH 1/1 arm: fix exception vectors
Hi Albert,
Quoted 45 lines · Albert ARIBAUD
Hello Luca,
Quoted 35 lines · Luca Ellero
After relocation, exception vectors still point to the old code (not relocated). This patch fixes them.
Signed-off-by Luca Ellero <[email protected]>--- arch/arm/lib/relocate.S | 15 +++++++++++++++ 1 file changed, 15 insertions(+)arch/arm/lib/relocate.S +15
-1@@ -76,6 +76,21 @@ copy_loop: blo copy_loop /* + * fix exception vectors + */ + ldr r2, =_undefined_instruction + ldr r3, =_fiq + add r2, r2, r4 + add r3, r3, r4 +fix_exceptions: + ldr r0, [r2] + add r0, r0, r4 + str r0, [r2] + cmp r2,r3 + add r2, #4 + blo fix_exceptions + + /* * fix .rel.dyn relocations */ ldr r2, =__rel_dyn_start /* r2 <- SRC &__rel_dyn_start */ --Quoted 2 lines
1.7.10.4
There is already a mechanism to relocate vectors (do a git grep for '
relocate_vectors' which takes into account various ISA and SoC cases.
Quoted 1 line
Can you describe the use case which you are encountering?
As far as I can see the mechanism to relocate vectors is implemented only on iMX25/27 and involves high vectors address (0xFFFFxxxx).
The problem is that, after relocation, U-Boot doesn't fix the vector table addresses, they still point to the old addresses (before relocation). This is wrong and this patch fixes them to point to the new addresses.
I had to use this patch trying to implement IRQ support for a Freescale iMX6 board. iMX6 does not provide RAM at the high vectors address and trying to access them leads to errors, so I couldn't use them.
Regards
Signature · 4 lines
Luca Ellero E-mail: luca.ellero at brickedbrain.com Internet: www.brickedbrain.com
PATCH 1/1 arm: fix exception vectors
Hello Luca,
Quoted 48 lines · Luca Ellero
Hi Albert,
Quoted 45 lines · Albert ARIBAUD
Hello Luca,
Quoted 35 lines · Luca Ellero
After relocation, exception vectors still point to the old code (not relocated). This patch fixes them.
Signed-off-by Luca Ellero <[email protected]>--- arch/arm/lib/relocate.S | 15 +++++++++++++++ 1 file changed, 15 insertions(+)arch/arm/lib/relocate.S +15
-1@@ -76,6 +76,21 @@ copy_loop: blo copy_loop /* + * fix exception vectors + */ + ldr r2, =_undefined_instruction + ldr r3, =_fiq + add r2, r2, r4 + add r3, r3, r4 +fix_exceptions: + ldr r0, [r2] + add r0, r0, r4 + str r0, [r2] + cmp r2,r3 + add r2, #4 + blo fix_exceptions + + /* * fix .rel.dyn relocations */ ldr r2, =__rel_dyn_start /* r2 <- SRC &__rel_dyn_start */ --Quoted 2 lines
1.7.10.4
There is already a mechanism to relocate vectors (do a git grep for '
relocate_vectors' which takes into account various ISA and SoC cases.
Quoted 4 lines
Quoted 1 line
Can you describe the use case which you are encountering?
As far as I can see the mechanism to relocate vectors is implemented only on iMX25/27 and involves high vectors address (0xFFFFxxxx).
You are correct that the mechanism is /used/ only by mx25 and mx27.
However, it has been introduced to support /all/ SoCs (or even boards), not only mx25, mx27, and /all/ exception vector handling scenarios, not only high vectors addresses.
Actually, the standard high and low address is handled by default, and mx25 and mx27 are cases where this default is overriden /because/ high or low vector addresses are *unapplicable* for them due to their memory mapping.
Quoted 3 lines
The problem is that, after relocation, U-Boot doesn't fix the vector table addresses, they still point to the old addresses (before relocation). This is wrong and this patch fixes them to point to the new addresses.
You are right about the problem, and this problem is exactly what the relocate_vectors mechanism is here to fix -- exactly the same problem mx25 and mx27 had before we fixed it (quite recently actually, as it was done mid-November, between 2015.01-rc1 and 2015.01-rc1 rc2).
Quoted 3 lines
I had to use this patch trying to implement IRQ support for a Freescale iMX6 board. iMX6 does not provide RAM at the high vectors address and trying to access them leads to errors, so I couldn't use them.
This is *exactly* the case where you should define your own version of relocate_vectors (probably at SoC level).
Quoted 4 lines
Regards
Signature · 1 line
Luca Ellero
Amicalement,
Signature · 1 line
Albert.
PATCH 1/1 arm: fix exception vectors
Hi Albert,
Quoted 77 lines · Albert ARIBAUD
Hello Luca,
Quoted 48 lines · Luca Ellero
Hi Albert,
Quoted 45 lines · Albert ARIBAUD
Hello Luca,
Quoted 35 lines · Luca Ellero
After relocation, exception vectors still point to the old code (not relocated). This patch fixes them.
Signed-off-by Luca Ellero <[email protected]>--- arch/arm/lib/relocate.S | 15 +++++++++++++++ 1 file changed, 15 insertions(+)arch/arm/lib/relocate.S +15
-1@@ -76,6 +76,21 @@ copy_loop: blo copy_loop /* + * fix exception vectors + */ + ldr r2, =_undefined_instruction + ldr r3, =_fiq + add r2, r2, r4 + add r3, r3, r4 +fix_exceptions: + ldr r0, [r2] + add r0, r0, r4 + str r0, [r2] + cmp r2,r3 + add r2, #4 + blo fix_exceptions + + /* * fix .rel.dyn relocations */ ldr r2, =__rel_dyn_start /* r2 <- SRC &__rel_dyn_start */ --Quoted 2 lines
1.7.10.4
There is already a mechanism to relocate vectors (do a git grep for '
relocate_vectors' which takes into account various ISA and SoC cases.Quoted 4 lines
Quoted 1 line
Can you describe the use case which you are encountering?
As far as I can see the mechanism to relocate vectors is implemented only on iMX25/27 and involves high vectors address (0xFFFFxxxx).
You are correct that the mechanism is /used/ only by mx25 and mx27.
However, it has been introduced to support /all/ SoCs (or even boards), not only mx25, mx27, and /all/ exception vector handling scenarios, not only high vectors addresses.
Actually, the standard high and low address is handled by default, and mx25 and mx27 are cases where this default is overriden /because/ high or low vector addresses are *unapplicable* for them due to their memory mapping.
Quoted 3 lines
The problem is that, after relocation, U-Boot doesn't fix the vector table addresses, they still point to the old addresses (before relocation). This is wrong and this patch fixes them to point to the new addresses.
You are right about the problem, and this problem is exactly what the
relocate_vectorsmechanism is here to fix -- exactly the same problem mx25 and mx27 had before we fixed it (quite recently actually, as it was done mid-November, between 2015.01-rc1 and 2015.01-rc1 rc2).
Quoted 7 lines
Quoted 3 lines
I had to use this patch trying to implement IRQ support for a Freescale iMX6 board. iMX6 does not provide RAM at the high vectors address and trying to access them leads to errors, so I couldn't use them.
This is *exactly* the case where you should define your own version of
relocate_vectors(probably at SoC level).
Ok, I will try to implement it as you suggested.
Thank you
regards
Luca
Signature · 4 lines
Luca Ellero E-mail: luca.ellero at brickedbrain.com Internet: www.brickedbrain.com
PATCH 1/1 arm: fix exception vectors
In reply to Albert ARIBAUDQuoted 5 lines
On Mon, 19 Jan 2015 11:11:34 +0100, Luca Ellero
Quoted 2 lines
As far as I can see the mechanism to relocate vectors is implemented only on iMX25/27 and involves high vectors address (0xFFFFxxxx).
Quoted 17 lines · albert.u.boot at aribaud.net
You are correct that the mechanism is /used/ only by mx25 and mx27.
However, it has been introduced to support /all/ SoCs (or even boards), not only mx25, mx27, and /all/ exception vector handling scenarios, not only high vectors addresses.
Actually, the standard high and low address is handled by default, and mx25 and mx27 are cases where this default is overriden /because/ high or low vector addresses are *unapplicable* for them due to their memory mapping.
On Mon, 19 Jan 2015 11:11:34 +0100, Luca Ellero
Quoted 4 lines
The problem is that, after relocation, U-Boot doesn't fix the vector table addresses, they still point to the old addresses (before relocation). This is wrong and this patch fixes them to point to the new addresses.
Quoted 11 lines · albert.u.boot at aribaud.net
You are right about the problem, and this problem is exactly what the
relocate_vectorsmechanism is here to fix -- exactly the same problem mx25 and mx27 had before we fixed it (quite recently actually, as it was done mid-November, between 2015.01-rc1 and 2015.01-rc1 rc2).On Mon, 19 Jan 2015 11:11:34 +0100, Luca Ellero
Quoted 4 lines
I had to use this patch trying to implement IRQ support for a Freescale iMX6 board. iMX6 does not provide RAM at the high vectors address and trying to access them leads to errors, so I couldn't use them.
Quoted 2 lines · albert.u.boot at aribaud.net
This is *exactly* the case where you should define your own version of
relocate_vectors(probably at SoC level).
A key difference is the ARM CPU architecture version. The ARMv7/Cortex on the imx6 will support vector table 'remaps'. Currently I see,
#ifdef CONFIG_HAS_VBAR
/*
* If the ARM processor has the security extensions,
* use VBAR to relocate the exception vectors.
*/
ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
mcr p15, 0, r0, c12, c0, 0 /* Set VBAR */#else
This should be available for the CPUs, but I don't see this symbol besides a 'Kconfig'. There are three versions on the Cortex, but the VBAR (whether secure or not) is the the correct one.
At least in theory, this code if activated should work for the iMx6 and an override of the 'weak' relocate vectors is not needed. I think trying to use the 'VBAR' is the correct way to go?
Fwiw,
Bill Pringlemeir.
PATCH 1/1 arm: fix exception vectors
Hello Bill,
Quoted 57 lines · Bill Pringlemeir
Quoted 5 lines
On Mon, 19 Jan 2015 11:11:34 +0100, Luca Ellero
Quoted 2 lines
As far as I can see the mechanism to relocate vectors is implemented only on iMX25/27 and involves high vectors address (0xFFFFxxxx).
Quoted 17 lines · albert.u.boot at aribaud.net
You are correct that the mechanism is /used/ only by mx25 and mx27.
However, it has been introduced to support /all/ SoCs (or even boards), not only mx25, mx27, and /all/ exception vector handling scenarios, not only high vectors addresses.
Actually, the standard high and low address is handled by default, and mx25 and mx27 are cases where this default is overriden /because/ high or low vector addresses are *unapplicable* for them due to their memory mapping.
On Mon, 19 Jan 2015 11:11:34 +0100, Luca Ellero
Quoted 4 lines
The problem is that, after relocation, U-Boot doesn't fix the vector table addresses, they still point to the old addresses (before relocation). This is wrong and this patch fixes them to point to the new addresses.
Quoted 11 lines · albert.u.boot at aribaud.net
You are right about the problem, and this problem is exactly what the
relocate_vectorsmechanism is here to fix -- exactly the same problem mx25 and mx27 had before we fixed it (quite recently actually, as it was done mid-November, between 2015.01-rc1 and 2015.01-rc1 rc2).On Mon, 19 Jan 2015 11:11:34 +0100, Luca Ellero
Quoted 4 lines
I had to use this patch trying to implement IRQ support for a Freescale iMX6 board. iMX6 does not provide RAM at the high vectors address and trying to access them leads to errors, so I couldn't use them.
Quoted 2 lines · albert.u.boot at aribaud.net
This is *exactly* the case where you should define your own version of
relocate_vectors(probably at SoC level).A key difference is the ARM CPU architecture version. The ARMv7/Cortex on the imx6 will support vector table 'remaps'. Currently I see,
#ifdef CONFIG_HAS_VBAR /* * If the ARM processor has the security extensions, * use VBAR to relocate the exception vectors. */ ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */ mcr p15, 0, r0, c12, c0, 0 /* Set VBAR */#else
Quoted 7 lines
This should be available for the CPUs, but I don't see this symbol besides a '
Kconfig'. There are three versions on the Cortex, but the VBAR (whether secure or not) is the the correct one.At least in theory, this code if activated should work for the iMx6 and an override of the 'weak' relocate vectors is not needed. I think trying to use the 'VBAR' is the correct way to go?
Possibly, though one should take into account the fact that the SoC design around the armv7 core (and the associated ROM code) might or might not allow changing the VBAR. Best is to look up the i.MX6 technical specs, especially the chapter on exceptions. If no specific indication is given that changing VBAR is forbidden, then yes, one should rely on CONFIG_HAS_VBAR (which should be set for all ARMv7-based targets).
Quoted 2 lines
Fwiw,
Bill Pringlemeir.
Amicalement,
Signature · 1 line
Albert.