Le mardi 24 février 2015 à 16:57 -0600, Nishanth Menon a écrit :
430973: Stale prediction on replaced inter working branch causes Cortex-A8 to execute in the wrong ARM/Thumb state Impacts: Everything lower than r2p1 Work around: Set IBE to 1
According to the Linux kernel source, this should only affect r1p* (hence, not r2p0): https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/ar...
454179: Stale prediction may inhibit target address misprediction on next predicted taken branch Impacts: Everything lower than r2p1 Work around: Set IBE and disable branch size mispredict to 1
621766: Under a specific set of conditions, executing a sequence of NEON or vfp load instructions can cause processor deadlock Impacts: Everything lower than r2p1 Work around: Set L1NEON to 1
Erratum 458693 also sets L1NEON bit and is said to only affect r2p0 according to the Linux kernel source: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/ar...
I'm not sure this is relevant (different erratum but similar workaround), but it seems odd to me.
Since the OMAP3 generation of processors have a wide variety of CPU revisions, it is more logical to enforce an implementation using revision checks.
Anyways, this worked just fine on my omap3630 device (> r2p1) and didn't trigger the errata workarounds. I reckon someone would have to test on a device that does require those workarounds (e.g. omap35xx).
Signed-off-by: Nishanth Menon nm@ti.com
README | 3 +++ arch/arm/cpu/armv7/omap3/board.c | 2 +- arch/arm/cpu/armv7/omap3/lowlevel_init.S | 37 +++++++++++++++++++++++++++ arch/arm/include/asm/arch-omap3/sys_proto.h | 1 + 4 files changed, 42 insertions(+), 1 deletion(-)
diff --git a/README b/README index d76cdc68d406..f309e27bbd02 100644 --- a/README +++ b/README @@ -625,6 +625,9 @@ The following options need to be configured: with CONFIG_ARM_ARCH_CP15_ERRATA define. These need to have an SoC specific implementation of the erratum workaround to function.
CONFIG_ARM_ERRATA_430973CONFIG_ARM_ERRATA_454179CONFIG_ARM_ERRATA_621766
- Driver Model
diff --git a/arch/arm/cpu/armv7/omap3/board.c b/arch/arm/cpu/armv7/omap3/board.c index 51abc4b09e36..7ce30949a6c6 100644 --- a/arch/arm/cpu/armv7/omap3/board.c +++ b/arch/arm/cpu/armv7/omap3/board.c @@ -408,7 +408,7 @@ static void omap3_emu_romcode_call(u32 service_id, u32 *parameters) do_omap3_emu_romcode_call(service_id, OMAP3_PUBLIC_SRAM_SCRATCH_AREA); }
-static void omap3_update_aux_cr_secure(u32 set_bits, u32 clear_bits) +void omap3_update_aux_cr_secure(u32 set_bits, u32 clear_bits) { u32 acr;
diff --git a/arch/arm/cpu/armv7/omap3/lowlevel_init.S b/arch/arm/cpu/armv7/omap3/lowlevel_init.S index 84591b8b5bab..b8e6ebccd4e7 100644 --- a/arch/arm/cpu/armv7/omap3/lowlevel_init.S +++ b/arch/arm/cpu/armv7/omap3/lowlevel_init.S @@ -48,6 +48,43 @@ ENTRY(do_omap3_emu_romcode_call) POP {r4-r12, pc} ENDPROC(do_omap3_emu_romcode_call)
+#ifdef CONFIG_ARM_ARCH_CP15_ERRATA
- .globl arch_cp15_errata_workaround
+/*
- R0 has MIDR
- R1 has CPU Variant (bits 20-23)
- R2 has CPU Revision (bits 0-3)
- R3 is compbined CPU variant << 4 + CPU revision
- */
+ENTRY(arch_cp15_errata_workaround)
- push {r4-r12, lr} @ save registers - ROM code may pollute
- mov r0, #0 @ Nothing to set in ACR
- mov r1, #0 @ Nothing to clear in ACR
+#ifdef CONFIG_ARM_ERRATA_454179
- cmp r3, #0x21 @ Only on < r2p1
- orrlt r0, r0, #(0x3 << 6) @ Set DBSM(BIT7) and IBE(BIT6) bits
+#endif
+#ifdef CONFIG_ARM_ERRATA_430973
- cmp r3, #0x21 @ Only on < r2p1
- orrlt r0, r0, #(0x1 << 6) @ Set IBE bit
+#endif
+#ifdef CONFIG_ARM_ERRATA_621766
- cmp r3, #0x21 @ Only on < r2p1
- orrlt r0, r0, #(0x1 << 5) @ Set L1NEON bit
+#endif
- add r2, r1, r0
- teq r2, #0 @ See if nothing to set or clear
- bne omap3_update_aux_cr_secure @update as per ROM code configuration needs
- pop {r4-r12, pc} @restore the registers back.
+ENDPROC(arch_cp15_errata_workaround) +#endif
#if !defined(CONFIG_SYS_NAND_BOOT) && !defined(CONFIG_SYS_NAND_BOOT) /**************************************************************************
- cpy_clk_code: relocates clock code into SRAM where its safer to execute
diff --git a/arch/arm/include/asm/arch-omap3/sys_proto.h b/arch/arm/include/asm/arch-omap3/sys_proto.h index c06605d533d3..56126fe8e863 100644 --- a/arch/arm/include/asm/arch-omap3/sys_proto.h +++ b/arch/arm/include/asm/arch-omap3/sys_proto.h @@ -74,5 +74,6 @@ void dieid_num_r(void); void get_dieid(u32 *id); void do_omap3_emu_romcode_call(u32 service_id, u32 parameters); void omap_smc1(u32 service, u32 val); +void omap3_update_aux_cr_secure(u32 set_bits, u32 clear_bits); u32 warm_reset(void); #endif