diff options
Diffstat (limited to 'arch/arm/mm/Kconfig')
| -rw-r--r-- | arch/arm/mm/Kconfig | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index c6c4c9c8824b..60cdfdc151aa 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -679,7 +679,7 @@ config ARCH_DMA_ADDR_T_64BIT bool config ARM_THUMB - bool "Support Thumb user binaries" if !CPU_THUMBONLY + bool "Support Thumb user binaries" if !CPU_THUMBONLY && EXPERT depends on CPU_THUMB_CAPABLE default y help @@ -690,6 +690,10 @@ config ARM_THUMB instruction set resulting in smaller binaries at the expense of slightly less efficient code. + If this option is disabled, and you run userspace that switches to + Thumb mode, signal handling will not work correctly, resulting in + segmentation faults or illegal instruction aborts. + If you don't know what this all is, saying Y is a safe choice. config ARM_THUMBEE @@ -1045,8 +1049,8 @@ config ARM_L1_CACHE_SHIFT default 5 config ARM_DMA_MEM_BUFFERABLE - bool "Use non-cacheable memory for DMA" if (CPU_V6 || CPU_V6K) && !CPU_V7 - default y if CPU_V6 || CPU_V6K || CPU_V7 + bool "Use non-cacheable memory for DMA" if (CPU_V6 || CPU_V6K || CPU_V7M) && !CPU_V7 + default y if CPU_V6 || CPU_V6K || CPU_V7 || CPU_V7M help Historically, the kernel has used strongly ordered mappings to provide DMA coherent memory. With the advent of ARMv7, mapping @@ -1061,6 +1065,10 @@ config ARM_DMA_MEM_BUFFERABLE and therefore turning this on may result in unpredictable driver behaviour. Therefore, we offer this as an option. + On some of the beefier ARMv7-M machines (with DMA and write + buffers) you likely want this enabled, while those that + didn't need it until now also won't need it in the future. + You are recommended say 'Y' here and debug any affected drivers. config ARM_HEAVY_MB |