Commit 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing
stack pointer while in RTAS") changes the code to use a field in
thread struct to store the stack pointer while in RTAS instead of
using SPRN_SPRG2. It therefore converts all places which were
manipulating SPRN_SPRG2 to use that field. During early startup,
the zeroing of SPRN_SPRG2 has been replaced by a zeroing of that
field in thread struct. But at least in start_here, that's done
wrongly because it used the physical address of the fields while
MMU is on at that time.
So the virtual address of the field should be used instead, but in
the meantime, thread struct has already been zeroised and initialised
so we can just drop this initialisation.
Reported-by: Larry Finger <[email protected]>
Fixes: 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing stack pointer while in RTAS")
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/kernel/head_32.S | 8 --------
1 file changed, 8 deletions(-)
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 48051c8977c5..e25b615e9f9e 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -851,10 +851,6 @@ __secondary_start:
tophys(r4,r2)
addi r4,r4,THREAD /* phys address of our thread_struct */
mtspr SPRN_SPRG_THREAD,r4
-#ifdef CONFIG_PPC_RTAS
- li r3,0
- stw r3, RTAS_SP(r4) /* 0 => not in RTAS */
-#endif
lis r4, (swapper_pg_dir - PAGE_OFFSET)@h
ori r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
mtspr SPRN_SPRG_PGDIR, r4
@@ -941,10 +937,6 @@ start_here:
tophys(r4,r2)
addi r4,r4,THREAD /* init task's THREAD */
mtspr SPRN_SPRG_THREAD,r4
-#ifdef CONFIG_PPC_RTAS
- li r3,0
- stw r3, RTAS_SP(r4) /* 0 => not in RTAS */
-#endif
lis r4, (swapper_pg_dir - PAGE_OFFSET)@h
ori r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
mtspr SPRN_SPRG_PGDIR, r4
--
2.13.3
On 3/25/19 3:43 AM, Christophe Leroy wrote:
> Commit 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing
> stack pointer while in RTAS") changes the code to use a field in
> thread struct to store the stack pointer while in RTAS instead of
> using SPRN_SPRG2. It therefore converts all places which were
> manipulating SPRN_SPRG2 to use that field. During early startup,
> the zeroing of SPRN_SPRG2 has been replaced by a zeroing of that
> field in thread struct. But at least in start_here, that's done
> wrongly because it used the physical address of the fields while
> MMU is on at that time.
>
> So the virtual address of the field should be used instead, but in
> the meantime, thread struct has already been zeroised and initialised
> so we can just drop this initialisation.
>
> Reported-by: Larry Finger <[email protected]>
> Fixes: 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing stack pointer while in RTAS")
> Signed-off-by: Christophe Leroy <[email protected]>
Tested-by: Larry Finger <[email protected]>
My PPC box now boots OK.
Larry
Michael,
Looks like you missed this fix for rc3.
Christophe
Le 25/03/2019 à 09:43, Christophe Leroy a écrit :
> Commit 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing
> stack pointer while in RTAS") changes the code to use a field in
> thread struct to store the stack pointer while in RTAS instead of
> using SPRN_SPRG2. It therefore converts all places which were
> manipulating SPRN_SPRG2 to use that field. During early startup,
> the zeroing of SPRN_SPRG2 has been replaced by a zeroing of that
> field in thread struct. But at least in start_here, that's done
> wrongly because it used the physical address of the fields while
> MMU is on at that time.
>
> So the virtual address of the field should be used instead, but in
> the meantime, thread struct has already been zeroised and initialised
> so we can just drop this initialisation.
>
> Reported-by: Larry Finger <[email protected]>
> Fixes: 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing stack pointer while in RTAS")
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
> arch/powerpc/kernel/head_32.S | 8 --------
> 1 file changed, 8 deletions(-)
>
> diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
> index 48051c8977c5..e25b615e9f9e 100644
> --- a/arch/powerpc/kernel/head_32.S
> +++ b/arch/powerpc/kernel/head_32.S
> @@ -851,10 +851,6 @@ __secondary_start:
> tophys(r4,r2)
> addi r4,r4,THREAD /* phys address of our thread_struct */
> mtspr SPRN_SPRG_THREAD,r4
> -#ifdef CONFIG_PPC_RTAS
> - li r3,0
> - stw r3, RTAS_SP(r4) /* 0 => not in RTAS */
> -#endif
> lis r4, (swapper_pg_dir - PAGE_OFFSET)@h
> ori r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
> mtspr SPRN_SPRG_PGDIR, r4
> @@ -941,10 +937,6 @@ start_here:
> tophys(r4,r2)
> addi r4,r4,THREAD /* init task's THREAD */
> mtspr SPRN_SPRG_THREAD,r4
> -#ifdef CONFIG_PPC_RTAS
> - li r3,0
> - stw r3, RTAS_SP(r4) /* 0 => not in RTAS */
> -#endif
> lis r4, (swapper_pg_dir - PAGE_OFFSET)@h
> ori r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
> mtspr SPRN_SPRG_PGDIR, r4
>
On Mon, 2019-03-25 at 08:43:33 UTC, Christophe Leroy wrote:
> Commit 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing
> stack pointer while in RTAS") changes the code to use a field in
> thread struct to store the stack pointer while in RTAS instead of
> using SPRN_SPRG2. It therefore converts all places which were
> manipulating SPRN_SPRG2 to use that field. During early startup,
> the zeroing of SPRN_SPRG2 has been replaced by a zeroing of that
> field in thread struct. But at least in start_here, that's done
> wrongly because it used the physical address of the fields while
> MMU is on at that time.
>
> So the virtual address of the field should be used instead, but in
> the meantime, thread struct has already been zeroised and initialised
> so we can just drop this initialisation.
>
> Reported-by: Larry Finger <[email protected]>
> Fixes: 0df977eafc79 ("powerpc/6xx: Don't use SPRN_SPRG2 for storing stack pointer while in RTAS")
> Signed-off-by: Christophe Leroy <[email protected]>
> Tested-by: Larry Finger <[email protected]>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/fd427103e8dfcb4b438269afd710b63e
cheers