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Groups > linux.kernel > #1365964 > unrolled thread
| Started by | Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de> |
|---|---|
| First post | 2016-03-29 09:50 +0200 |
| Last post | 2016-03-29 10:50 +0200 |
| Articles | 4 — 2 participants |
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[PATCH] arm: remove tautologic #ifdefs in proc-v7-3level.S Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de> - 2016-03-29 09:50 +0200
Re: [PATCH] arm: remove tautologic #ifdefs in proc-v7-3level.S Arnd Bergmann <arnd@arndb.de> - 2016-03-29 10:10 +0200
Re: [PATCH] arm: remove tautologic #ifdefs in proc-v7-3level.S Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de> - 2016-03-29 10:40 +0200
Re: [PATCH] arm: remove tautologic #ifdefs in proc-v7-3level.S Arnd Bergmann <arnd@arndb.de> - 2016-03-29 10:50 +0200
| From | Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de> |
|---|---|
| Date | 2016-03-29 09:50 +0200 |
| Subject | [PATCH] arm: remove tautologic #ifdefs in proc-v7-3level.S |
| Message-ID | <rhWzw-2QS-29@gated-at.bofh.it> |
The file arch/arm/mm/proc-v7-3level.S is only used by the #include directive in arch/arm/mm/proc-v7.S:23. This #include is conditional and depends on CONFIG_ARM_LPAE (otherwise proc-v7-2level.S is used). CONFIG_ARM_LPAE has a dependency on CONFIG_MMU defined in Kconfig. Consequently, checks for CONFIG_MMU in proc-v7-3level.S are superfluous. Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de> --- I detected the issue with chimaera, a tool I currently develop for my bachelor thesis extending the undertaker tool suite (https://undertaker.cs.fau.de). arch/arm/mm/proc-v7-3level.S | 4 ---- 1 file changed, 4 deletions(-) diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S index 5e5720e..6903f34 100644 --- a/arch/arm/mm/proc-v7-3level.S +++ b/arch/arm/mm/proc-v7-3level.S @@ -55,13 +55,11 @@ * the new TTB). */ ENTRY(cpu_v7_switch_mm) -#ifdef CONFIG_MMU mmid r2, r2 asid r2, r2 orr rpgdh, rpgdh, r2, lsl #(48 - 32) @ upper 32-bits of pgd mcrr p15, 0, rpgdl, rpgdh, c2 @ set TTB 0 isb -#endif ret lr ENDPROC(cpu_v7_switch_mm) @@ -81,7 +79,6 @@ ENDPROC(cpu_v7_switch_mm) * - pte - PTE value to store (64-bit in r2 and r3) */ ENTRY(cpu_v7_set_pte_ext) -#ifdef CONFIG_MMU tst rl, #L_PTE_VALID beq 1f tst rh, #1 << (57 - 32) @ L_PTE_NONE @@ -97,7 +94,6 @@ ENTRY(cpu_v7_set_pte_ext) 1: strd r2, r3, [r0] ALT_SMP(W(nop)) ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte -#endif ret lr ENDPROC(cpu_v7_set_pte_ext) -- 2.7.3
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| From | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| Date | 2016-03-29 10:10 +0200 |
| Message-ID | <rhWST-3dU-27@gated-at.bofh.it> |
| In reply to | #1365964 |
On Tuesday 29 March 2016 09:37:51 Jonas Rabenstein wrote:
> The file arch/arm/mm/proc-v7-3level.S is only used by the #include
> directive in arch/arm/mm/proc-v7.S:23. This #include is conditional and
> depends on CONFIG_ARM_LPAE (otherwise proc-v7-2level.S is used).
> CONFIG_ARM_LPAE has a dependency on CONFIG_MMU defined in Kconfig.
> Consequently, checks for CONFIG_MMU in proc-v7-3level.S are superfluous.
>
> Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
> ---
> I detected the issue with chimaera, a tool I currently develop for my bachelor
> thesis extending the undertaker tool suite (https://undertaker.cs.fau.de).
Nice catch!
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
I guess you should submit the same thing for the other file as well,
either in the same patch or as a series.
You can also add
Fixes: 8d2cd3a38fd6 ("ARM: LPAE: Factor out classic-MMU specific code into proc-v7-2level.S")
to mark the commit that led to the situation.
Arnd
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| From | Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de> |
|---|---|
| Date | 2016-03-29 10:40 +0200 |
| Message-ID | <rhXlT-3nw-9@gated-at.bofh.it> |
| In reply to | #1365980 |
On Tue, Mar 29, 2016 at 10:05:58AM +0200, Arnd Bergmann wrote:
> On Tuesday 29 March 2016 09:37:51 Jonas Rabenstein wrote:
> > The file arch/arm/mm/proc-v7-3level.S is only used by the #include
> > directive in arch/arm/mm/proc-v7.S:23. This #include is conditional and
> > depends on CONFIG_ARM_LPAE (otherwise proc-v7-2level.S is used).
> > CONFIG_ARM_LPAE has a dependency on CONFIG_MMU defined in Kconfig.
> > Consequently, checks for CONFIG_MMU in proc-v7-3level.S are superfluous.
> >
> > Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
> > ---
> > I detected the issue with chimaera, a tool I currently develop for my bachelor
> > thesis extending the undertaker tool suite (https://undertaker.cs.fau.de).
>
> Nice catch!
>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
>
> I guess you should submit the same thing for the other file as well,
> either in the same patch or as a series.
I do not get, what you mean with 'the other file'? For the
proc-v7-2level.S this precondition does not hold, as proc-v7-2level.S is
included if !CONFIG_ARM_LPAE. Consequently, no evidence about the MMU
state is available in their.
> You can also add
>
> Fixes: 8d2cd3a38fd6 ("ARM: LPAE: Factor out classic-MMU specific code into proc-v7-2level.S")
Shouldn't it be:
Fixes: 1b6ba46b7efa ("ARM: LPAE: MMU setup for the 3-level page table
format")?
Thanks for your help and advice,
Jonas
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| From | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| Date | 2016-03-29 10:50 +0200 |
| Message-ID | <rhXvz-3qM-5@gated-at.bofh.it> |
| In reply to | #1365999 |
On Tuesday 29 March 2016 10:29:11 Jonas Rabenstein wrote:
> On Tue, Mar 29, 2016 at 10:05:58AM +0200, Arnd Bergmann wrote:
> > On Tuesday 29 March 2016 09:37:51 Jonas Rabenstein wrote:
> > > The file arch/arm/mm/proc-v7-3level.S is only used by the #include
> > > directive in arch/arm/mm/proc-v7.S:23. This #include is conditional and
> > > depends on CONFIG_ARM_LPAE (otherwise proc-v7-2level.S is used).
> > > CONFIG_ARM_LPAE has a dependency on CONFIG_MMU defined in Kconfig.
> > > Consequently, checks for CONFIG_MMU in proc-v7-3level.S are superfluous.
> > >
> > > Signed-off-by: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
> > > ---
> > > I detected the issue with chimaera, a tool I currently develop for my bachelor
> > > thesis extending the undertaker tool suite (https://undertaker.cs.fau.de).
> >
> > Nice catch!
> >
> > Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> >
> > I guess you should submit the same thing for the other file as well,
> > either in the same patch or as a series.
> I do not get, what you mean with 'the other file'? For the
> proc-v7-2level.S this precondition does not hold, as proc-v7-2level.S is
> included if !CONFIG_ARM_LPAE. Consequently, no evidence about the MMU
> state is available in their.
My mistake. I misread this as the both files being used only for
MMU-enabled kernels, which would make sense because they deal with
page tables that are not being used without MMU, but they are in fact
being compiled anyway.
> > You can also add
> >
> > Fixes: 8d2cd3a38fd6 ("ARM: LPAE: Factor out classic-MMU specific code into proc-v7-2level.S")
> Shouldn't it be:
> Fixes: 1b6ba46b7efa ("ARM: LPAE: MMU setup for the 3-level page table
> format")?
Nevermind then. My line was incorrect, and the other one is a bit
redundant as it is the one that adds the file in the first place.
Arnd
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