From: Huang Tao <huangtao@xxxxxxxxxxxxxx> On Cortex-A12 (r0p0..r0p1-00lac0-rc11), when a CPU executes a sequence of two conditional store instructions with opposite condition code and updating the same register, the system might enter a deadlock if the second conditional instruction is an UNPREDICTABLE STR or STM instruction. This workaround setting bit[12] of the Feature Register prevents the erratum. This bit disables an optimisation applied to a sequence of 2 instructions that use opposing condition codes. Signed-off-by: Huang Tao <huangtao at rock-chips.com> Signed-off-by: Kever Yang <kever.yang at rock-chips.com> Signed-off-by: Caesar Wang <wxt at rock-chips.com> --- arch/arm/Kconfig | 13 +++++++++++++ arch/arm/mm/proc-v7.S | 12 ++++++++++++ 2 files changed, 25 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 639411f..554b57a 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1263,6 +1263,19 @@ config ARM_ERRATA_773022 loop buffer may deliver incorrect instructions. This workaround disables the loop buffer to avoid the erratum. +config ARM_ERRATA_818325 + bool "ARM errata: Execution of an UNPREDICTABLE STR or STM instruction might deadlock" + depends on CPU_V7 + help + This option enables the workaround for the 818325 Cortex-A12 + (r0p0..r0p1-00lac0-rc11) erratum. When a CPU executes a sequence of + two conditional store instructions with opposite condition code and + updating the same register, the system might enter a deadlock if the + second conditional instruction is an UNPREDICTABLE STR or STM + instruction. This workaround setting bit[12] of the Feature Register + prevents the erratum. This bit disables an optimisation applied to a + sequence of 2 instructions that use opposing condition codes. + endmenu source "arch/arm/common/Kconfig" diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index de2b246..2b338ec 100644 --- a/arch/arm/mm/proc-v7.S +++ b/arch/arm/mm/proc-v7.S @@ -439,6 +439,18 @@ __v7_setup_cont: teq r0, r10 beq __ca9_errata + /* Cortex-A12 Errata */ + ldr r10, =0x00000c0d @ Cortex-A12 primary part number + teq r0, r10 + bne 5f +#ifdef CONFIG_ARM_ERRATA_818325 + teq r6, #0x00 @ present in r0p0 + teqne r6, #0x01 @ present in r0p1-00lac0-rc11 + mrceq p15, 0, r10, c15, c0, 1 @ read diagnostic register + orreq r10, r10, #1 << 12 @ set bit #12 + mcreq p15, 0, r10, c15, c0, 1 @ write diagnostic register + isb +#endif /* Cortex-A15 Errata */ ldr r10, =0x00000c0f @ Cortex-A15 primary part number teq r0, r10 -- 1.9.1
