Hi all, The "Power Architecture 64-Bit ELF V2 ABI" says in section 2.3.2.3: [...] There are several rules that must be adhered to in order to ensure reliable and consistent call chain backtracing: * Before a function calls any other function, it shall establish its own stack frame, whose size shall be a multiple of 16 bytes. – In instances where a function’s prologue creates a stack frame, the back-chain word of the stack frame shall be updated atomically with the value of the stack pointer (r1) when a back chain is implemented. (This must be supported as default by all ELF V2 ABI-compliant environments.) [...] – The function shall save the link register that contains its return address in the LR save doubleword of its caller’s stack frame before calling another function. To me this sounds like the equivalent of HAVE_RELIABLE_STACKTRACE. This patch may be unneccessarily limited to ppc64le, but OTOH the only user of this flag so far is livepatching, which is only implemented on PPCs with 64-LE, a.k.a. ELF ABI v2. Signed-off-by: Torsten Duwe <duwe@xxxxxxx> --- diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index c51e6ce42e7a..3e3a6ab2e089 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -218,6 +218,7 @@ config PPC select HAVE_PERF_USER_STACK_DUMP select HAVE_RCU_TABLE_FREE if SMP select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_RELIABLE_STACKTRACE if PPC64 && CPU_LITTLE_ENDIAN select HAVE_SYSCALL_TRACEPOINTS select HAVE_VIRT_CPU_ACCOUNTING select HAVE_IRQ_TIME_ACCOUNTING -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
