Re: [PATCH v2 2/5] sunxi: move Cortex SMPEN setting into start.S

On 1/31/22 7:41 PM, Andre Przywara wrote:

According to their TRMs, Cortex ARMv7 CPUs with SMP support require the ACTLR.SMPEN bit to be set as early as possible, before any cache or TLB maintenance operations are done. As we do those things still in start.S, we need to move the SMPEN bit setting there, too.

This introduces a new ARMv7 wide symbol and code to set bit 6 in ACTLR very early in start.S, and moves sunxi boards over to use that instead of the custom code we had in our board.c file (where it was called technically too late).

In practice we got away with this so far, because at this point all the other cores were still in reset, so any broadcasting would have been ignored anyway. But it is architecturally cleaner to do it early, and we move a core specific piece of code out of board.c.

This also gets rid of the ARM_CORTEX_CPU_IS_UP kludge I introduced a few years back, and moves the respective logic into the new Kconfig entry.

Signed-off-by: Andre Przywara andre.przywara@arm.com

arch/arm/Kconfig | 3 --- arch/arm/cpu/armv7/Kconfig | 5 +++++ arch/arm/cpu/armv7/start.S | 11 +++++++++++ arch/arm/mach-sunxi/Kconfig | 6 ++++-- arch/arm/mach-sunxi/board.c | 9 --------- 5 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 6b11c3a50d9..7893d74fab2 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -452,9 +452,6 @@ config ENABLE_ARM_SOC_BOOT0_HOOK values, then choose this option, and create a file included as <asm/arch/boot0.h> which contains the required assembler code.

-config ARM_CORTEX_CPU_IS_UP

• bool

config USE_ARCH_MEMCPY bool "Use an assembly optimized implementation of memcpy" default y if !ARM64 diff --git a/arch/arm/cpu/armv7/Kconfig b/arch/arm/cpu/armv7/Kconfig index 60bb0a9e1ec..cc4684cfed3 100644 --- a/arch/arm/cpu/armv7/Kconfig +++ b/arch/arm/cpu/armv7/Kconfig @@ -76,4 +76,9 @@ config ARMV7_LPAE Say Y here to use the long descriptor page table format. This is required if U-Boot runs in HYP mode.

+config ARMV7_SET_CORTEX_SMPEN

• bool
• help

•  Enable the ARM Cortex ACTLR.SMP enable bit on startup.
  

endif diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S index 698e15b8e18..af87a5432ae 100644 --- a/arch/arm/cpu/armv7/start.S +++ b/arch/arm/cpu/armv7/start.S @@ -173,6 +173,17 @@ ENDPROC(switch_to_hypervisor)

*************************************************************************/ ENTRY(cpu_init_cp15)

+#if CONFIG_IS_ENABLED(ARMV7_SET_CORTEX_SMPEN)

There is no SPL-prefixed symbol, so you probably want plain old "#if defined" here instead. Otherwise, this code will always be omitted from SPL.

Regards, Samuel

• /*

• * The Arm Cortex-A7 TRM says this bit must be enabled before
  

• * "any cache or TLB maintenance operations are performed".
  

• */
  

• mrc p15, 0, r0, c1, c0, 1 @ read auxilary control register
• orr r0, r0, #1 << 6 @ set SMP bit to enable coherency
• mcr p15, 0, r0, c1, c0, 1 @ write auxilary control register

+#endif

• /*
  • Invalidate L1 I/D
  */

diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig index d7f9a03152f..637b1fb79e0 100644 --- a/arch/arm/mach-sunxi/Kconfig +++ b/arch/arm/mach-sunxi/Kconfig @@ -186,7 +186,6 @@ choice config MACH_SUN4I bool "sun4i (Allwinner A10)" select CPU_V7A

• select ARM_CORTEX_CPU_IS_UP select PHY_SUN4I_USB select DRAM_SUN4I select SUNXI_GEN_SUN4I

@@ -197,7 +196,6 @@ config MACH_SUN4I config MACH_SUN5I bool "sun5i (Allwinner A13)" select CPU_V7A

• select ARM_CORTEX_CPU_IS_UP select DRAM_SUN4I select PHY_SUN4I_USB select SUNXI_GEN_SUN4I

@@ -212,6 +210,7 @@ config MACH_SUN6I select CPU_V7_HAS_NONSEC select CPU_V7_HAS_VIRT select ARCH_SUPPORT_PSCI

• select ARMV7_SET_CORTEX_SMPEN select DRAM_SUN6I select PHY_SUN4I_USB select SPL_I2C

@@ -227,6 +226,7 @@ config MACH_SUN7I select CPU_V7_HAS_NONSEC select CPU_V7_HAS_VIRT select ARCH_SUPPORT_PSCI

• select ARMV7_SET_CORTEX_SMPEN select DRAM_SUN4I select PHY_SUN4I_USB select SUNXI_GEN_SUN4I

@@ -315,6 +315,7 @@ config MACH_SUN8I_V3S config MACH_SUN9I bool "sun9i (Allwinner A80)" select CPU_V7A

• select ARMV7_SET_CORTEX_SMPEN select DRAM_SUN9I select SPL_I2C select SUN6I_PRCM

@@ -365,6 +366,7 @@ endchoice # The sun8i SoCs share a lot, this helps to avoid a lot of "if A23 || A33" config MACH_SUN8I bool

• select ARMV7_SET_CORTEX_SMPEN if !ARM64 select SUN6I_PRCM default y if MACH_SUN8I_A23 default y if MACH_SUN8I_A33

diff --git a/arch/arm/mach-sunxi/board.c b/arch/arm/mach-sunxi/board.c index c932a293317..261af9d7bf4 100644 --- a/arch/arm/mach-sunxi/board.c +++ b/arch/arm/mach-sunxi/board.c @@ -218,15 +218,6 @@ void s_init(void) /* A83T BSP never modifies SUNXI_SRAMC_BASE + 0x44 */ /* No H3 BSP, boot0 seems to not modify SUNXI_SRAMC_BASE + 0x44 */ #endif

-#if !defined(CONFIG_ARM_CORTEX_CPU_IS_UP) && !defined(CONFIG_ARM64)

• /* Enable SMP mode for CPU0, by setting bit 6 of Auxiliary Ctl reg */
• asm volatile(

• "mrc p15, 0, r0, c1, c0, 1\n"
  

• "orr r0, r0, #1 << 6\n"
  

• "mcr p15, 0, r0, c1, c0, 1\n"
  

• ::: "r0");
  

-#endif }

#define SUNXI_INVALID_BOOT_SOURCE -1