[PATCH AUTOSEL 6.6 4/6] ARM: 9420/1: smp: Fix SMP for xip kernels

[PATCH AUTOSEL 6.6 4/6] ARM: 9420/1: smp: Fix SMP for xip kernels

[Sasha Levin]

From: Harith G <harith.g@alifsemi.com>

[ Upstream commit 9e9b0cf9319b4db143014477b0bc4b39894248f1 ]

Fix the physical address calculation of the following to get smp working
on xip kernels.
- secondary_data needed for secondary cpu bootup.
- secondary_startup address passed through psci.
- identity mapped code region needed for enabling mmu for secondary cpus.

Signed-off-by: Harith George <harith.g@alifsemi.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/kernel/head.S     | 4 ++++
 arch/arm/kernel/psci_smp.c | 7 +++++++
 arch/arm/mm/idmap.c        | 7 +++++++
 3 files changed, 18 insertions(+)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 1ec35f065617e..e573adfe73b28 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -407,7 +407,11 @@ ENTRY(secondary_startup)
 	/*
 	 * Use the page tables supplied from  __cpu_up.
 	 */
+#ifdef CONFIG_XIP_KERNEL
+	ldr	r3, =(secondary_data + PLAT_PHYS_OFFSET - PAGE_OFFSET)
+#else
 	adr_l	r3, secondary_data
+#endif
 	mov_l	r12, __secondary_switched
 	ldrd	r4, r5, [r3, #0]		@ get secondary_data.pgdir
 ARM_BE8(eor	r4, r4, r5)			@ Swap r5 and r4 in BE:
diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c
index d4392e1774848..3bb0c4dcfc5c9 100644
--- a/arch/arm/kernel/psci_smp.c
+++ b/arch/arm/kernel/psci_smp.c
@@ -45,8 +45,15 @@ extern void secondary_startup(void);
 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
 	if (psci_ops.cpu_on)
+#ifdef CONFIG_XIP_KERNEL
+		return psci_ops.cpu_on(cpu_logical_map(cpu),
+			((phys_addr_t)(&secondary_startup)
+			- XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+			+ CONFIG_XIP_PHYS_ADDR));
+#else
 		return psci_ops.cpu_on(cpu_logical_map(cpu),
 					virt_to_idmap(&secondary_startup));
+#endif
 	return -ENODEV;
 }
 
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index 448e57c6f6534..4a833e89782aa 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -84,8 +84,15 @@ static void identity_mapping_add(pgd_t *pgd, const char *text_start,
 	unsigned long addr, end;
 	unsigned long next;
 
+#ifdef CONFIG_XIP_KERNEL
+	addr = (phys_addr_t)(text_start) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+		+ CONFIG_XIP_PHYS_ADDR;
+	end = (phys_addr_t)(text_end) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
+		+ CONFIG_XIP_PHYS_ADDR;
+#else
 	addr = virt_to_idmap(text_start);
 	end = virt_to_idmap(text_end);
+#endif
 	pr_info("Setting up static identity map for 0x%lx - 0x%lx\n", addr, end);
 
 	prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
-- 
2.43.0

[PATCH AUTOSEL 6.6 5/6] ARM: 9434/1: cfi: Fix compilation corner case

[Sasha Levin]

From: Linus Walleij <linus.walleij@linaro.org>

[ Upstream commit 4aea16b7cfb76bd3361858ceee6893ef5c9b5570 ]

When enabling expert mode CONFIG_EXPERT and using that power
user mode to disable the branch prediction hardening
!CONFIG_HARDEN_BRANCH_PREDICTOR, the assembly linker
in CLANG notices that some assembly in proc-v7.S does
not have corresponding C call sites, i.e. the prototypes
in proc-v7-bugs.c are enclosed in ifdef
CONFIG_HARDEN_BRANCH_PREDICTOR so this assembly:

SYM_TYPED_FUNC_START(cpu_v7_smc_switch_mm)
SYM_TYPED_FUNC_START(cpu_v7_hvc_switch_mm)

Results in:

ld.lld: error: undefined symbol: __kcfi_typeid_cpu_v7_smc_switch_mm
>>> referenced by proc-v7.S:94 (.../arch/arm/mm/proc-v7.S:94)
>>> arch/arm/mm/proc-v7.o:(.text+0x108) in archive vmlinux.a

ld.lld: error: undefined symbol: __kcfi_typeid_cpu_v7_hvc_switch_mm
>>> referenced by proc-v7.S:105 (.../arch/arm/mm/proc-v7.S:105)
>>> arch/arm/mm/proc-v7.o:(.text+0x124) in archive vmlinux.a

Fix this by adding an additional requirement that
CONFIG_HARDEN_BRANCH_PREDICTOR has to be enabled to compile
these assembly calls.

Closes: https://lore.kernel.org/oe-kbuild-all/202411041456.ZsoEiD7T-lkp@intel.com/

Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm/mm/proc-v7.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 193c7aeb67039..bea11f9bfe856 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -93,7 +93,7 @@ ENTRY(cpu_v7_dcache_clean_area)
 	ret	lr
 ENDPROC(cpu_v7_dcache_clean_area)
 
-#ifdef CONFIG_ARM_PSCI
+#if defined(CONFIG_ARM_PSCI) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
 	.arch_extension sec
 ENTRY(cpu_v7_smc_switch_mm)
 	stmfd	sp!, {r0 - r3}
-- 
2.43.0

Re: [PATCH AUTOSEL 6.6 5/6] ARM: 9434/1: cfi: Fix compilation corner case

[Nathan Chancellor]

Hi Sasha,

On Wed, Nov 20, 2024 at 09:06:35AM -0500, Sasha Levin wrote:
> From: Linus Walleij <linus.walleij@linaro.org>
> 
> [ Upstream commit 4aea16b7cfb76bd3361858ceee6893ef5c9b5570 ]
> 
> When enabling expert mode CONFIG_EXPERT and using that power
> user mode to disable the branch prediction hardening
> !CONFIG_HARDEN_BRANCH_PREDICTOR, the assembly linker
> in CLANG notices that some assembly in proc-v7.S does
> not have corresponding C call sites, i.e. the prototypes
> in proc-v7-bugs.c are enclosed in ifdef
> CONFIG_HARDEN_BRANCH_PREDICTOR so this assembly:
> 
> SYM_TYPED_FUNC_START(cpu_v7_smc_switch_mm)
> SYM_TYPED_FUNC_START(cpu_v7_hvc_switch_mm)
> 
> Results in:
> 
> ld.lld: error: undefined symbol: __kcfi_typeid_cpu_v7_smc_switch_mm
> >>> referenced by proc-v7.S:94 (.../arch/arm/mm/proc-v7.S:94)
> >>> arch/arm/mm/proc-v7.o:(.text+0x108) in archive vmlinux.a
> 
> ld.lld: error: undefined symbol: __kcfi_typeid_cpu_v7_hvc_switch_mm
> >>> referenced by proc-v7.S:105 (.../arch/arm/mm/proc-v7.S:105)
> >>> arch/arm/mm/proc-v7.o:(.text+0x124) in archive vmlinux.a
> 
> Fix this by adding an additional requirement that
> CONFIG_HARDEN_BRANCH_PREDICTOR has to be enabled to compile
> these assembly calls.
> 
> Closes: https://lore.kernel.org/oe-kbuild-all/202411041456.ZsoEiD7T-lkp@intel.com/
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  arch/arm/mm/proc-v7.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> index 193c7aeb67039..bea11f9bfe856 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -93,7 +93,7 @@ ENTRY(cpu_v7_dcache_clean_area)
>  	ret	lr
>  ENDPROC(cpu_v7_dcache_clean_area)
>  
> -#ifdef CONFIG_ARM_PSCI
> +#if defined(CONFIG_ARM_PSCI) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
>  	.arch_extension sec
>  ENTRY(cpu_v7_smc_switch_mm)

This patch is unnecessary in branches prior to 6.10 (when ARM started
supporting kCFI) because SYM_TYPED_FUNC_START() is not used here. I
would just drop it for 6.6 and earlier.

>  	stmfd	sp!, {r0 - r3}
> -- 
> 2.43.0
> 

Re: [PATCH AUTOSEL 6.6 5/6] ARM: 9434/1: cfi: Fix compilation corner case

[Sasha Levin]

On Wed, Nov 20, 2024 at 08:13:38AM -0700, Nathan Chancellor wrote:
>Hi Sasha,
>
>On Wed, Nov 20, 2024 at 09:06:35AM -0500, Sasha Levin wrote:
>> From: Linus Walleij <linus.walleij@linaro.org>
>>
>> [ Upstream commit 4aea16b7cfb76bd3361858ceee6893ef5c9b5570 ]
>>
>> When enabling expert mode CONFIG_EXPERT and using that power
>> user mode to disable the branch prediction hardening
>> !CONFIG_HARDEN_BRANCH_PREDICTOR, the assembly linker
>> in CLANG notices that some assembly in proc-v7.S does
>> not have corresponding C call sites, i.e. the prototypes
>> in proc-v7-bugs.c are enclosed in ifdef
>> CONFIG_HARDEN_BRANCH_PREDICTOR so this assembly:
>>
>> SYM_TYPED_FUNC_START(cpu_v7_smc_switch_mm)
>> SYM_TYPED_FUNC_START(cpu_v7_hvc_switch_mm)
>>
>> Results in:
>>
>> ld.lld: error: undefined symbol: __kcfi_typeid_cpu_v7_smc_switch_mm
>> >>> referenced by proc-v7.S:94 (.../arch/arm/mm/proc-v7.S:94)
>> >>> arch/arm/mm/proc-v7.o:(.text+0x108) in archive vmlinux.a
>>
>> ld.lld: error: undefined symbol: __kcfi_typeid_cpu_v7_hvc_switch_mm
>> >>> referenced by proc-v7.S:105 (.../arch/arm/mm/proc-v7.S:105)
>> >>> arch/arm/mm/proc-v7.o:(.text+0x124) in archive vmlinux.a
>>
>> Fix this by adding an additional requirement that
>> CONFIG_HARDEN_BRANCH_PREDICTOR has to be enabled to compile
>> these assembly calls.
>>
>> Closes: https://lore.kernel.org/oe-kbuild-all/202411041456.ZsoEiD7T-lkp@intel.com/
>>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Reviewed-by: Nathan Chancellor <nathan@kernel.org>
>> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
>> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
>> Signed-off-by: Sasha Levin <sashal@kernel.org>
>> ---
>>  arch/arm/mm/proc-v7.S | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
>> index 193c7aeb67039..bea11f9bfe856 100644
>> --- a/arch/arm/mm/proc-v7.S
>> +++ b/arch/arm/mm/proc-v7.S
>> @@ -93,7 +93,7 @@ ENTRY(cpu_v7_dcache_clean_area)
>>  	ret	lr
>>  ENDPROC(cpu_v7_dcache_clean_area)
>>
>> -#ifdef CONFIG_ARM_PSCI
>> +#if defined(CONFIG_ARM_PSCI) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR)
>>  	.arch_extension sec
>>  ENTRY(cpu_v7_smc_switch_mm)
>
>This patch is unnecessary in branches prior to 6.10 (when ARM started
>supporting kCFI) because SYM_TYPED_FUNC_START() is not used here. I
>would just drop it for 6.6 and earlier.

Ack, will do.

-- 
Thanks,
Sasha