3.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> commit 30cdef97107370a7f63ab5d80fd2de30540750c8 upstream. The ll_add_cpu_to_smp_group(), ll_enable_coherency() and ll_disable_coherency() are used on Armada XP to control the coherency fabric. However, they make the assumption that the coherency fabric is always available, which is currently a correct assumption but will no longer be true with a followup commit that disables the usage of the coherency fabric when the conditions are not met to use it. Therefore, this commit modifies those functions so that they check the return value of ll_get_coherency_base(), and if the return value is 0, they simply return without configuring anything in the coherency fabric. The ll_get_coherency_base() function is also modified to properly return 0 when the function is called with the MMU disabled. In this case, it normally returns the physical address of the coherency fabric, but we now check if the virtual address is 0, and if that's case, return a physical address of 0 to indicate that the coherency fabric is not enabled. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> Acked-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/1415871540-20302-2-git-send-email-thomas.petazzoni@xxxxxxxxxxxxxxxxxx Signed-off-by: Jason Cooper <jason@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm/mach-mvebu/coherency_ll.S | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) --- a/arch/arm/mach-mvebu/coherency_ll.S +++ b/arch/arm/mach-mvebu/coherency_ll.S @@ -24,7 +24,10 @@ #include <asm/cp15.h> .text -/* Returns the coherency base address in r1 (r0 is untouched) */ +/* + * Returns the coherency base address in r1 (r0 is untouched), or 0 if + * the coherency fabric is not enabled. + */ ENTRY(ll_get_coherency_base) mrc p15, 0, r1, c1, c0, 0 tst r1, #CR_M @ Check MMU bit enabled @@ -32,8 +35,13 @@ ENTRY(ll_get_coherency_base) /* * MMU is disabled, use the physical address of the coherency - * base address. + * base address. However, if the coherency fabric isn't mapped + * (i.e its virtual address is zero), it means coherency is + * not enabled, so we return 0. */ + ldr r1, =coherency_base + cmp r1, #0 + beq 2f adr r1, 3f ldr r3, [r1] ldr r1, [r1, r3] @@ -85,6 +93,9 @@ ENTRY(ll_add_cpu_to_smp_group) */ mov r0, lr bl ll_get_coherency_base + /* Bail out if the coherency is not enabled */ + cmp r1, #0 + reteq r0 bl ll_get_coherency_cpumask mov lr, r0 add r0, r1, #ARMADA_XP_CFB_CFG_REG_OFFSET @@ -107,6 +118,9 @@ ENTRY(ll_enable_coherency) */ mov r0, lr bl ll_get_coherency_base + /* Bail out if the coherency is not enabled */ + cmp r1, #0 + reteq r0 bl ll_get_coherency_cpumask mov lr, r0 add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET @@ -131,6 +145,9 @@ ENTRY(ll_disable_coherency) */ mov r0, lr bl ll_get_coherency_base + /* Bail out if the coherency is not enabled */ + cmp r1, #0 + reteq r0 bl ll_get_coherency_cpumask mov lr, r0 add r0, r1, #ARMADA_XP_CFB_CTL_REG_OFFSET -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html