From: Nicholas Piggin npiggin@gmail.com
This patch has been added to the 4.1 stable tree. If you have any objections, please let us know.
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[ Upstream commit 50e51c13b3822d14ff6df4279423e4b7b2269bc3 ]
The rfid/hrfid ((Hypervisor) Return From Interrupt) instruction is used for switching from the kernel to userspace, and from the hypervisor to the guest kernel. However it can and is also used for other transitions, eg. from real mode kernel code to virtual mode kernel code, and it's not always clear from the code what the destination context is.
To make it clearer when reading the code, add macros which encode the expected destination context.
Signed-off-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- arch/powerpc/include/asm/exception-64e.h | 6 ++++++ arch/powerpc/include/asm/exception-64s.h | 29 +++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+)
diff --git a/arch/powerpc/include/asm/exception-64e.h b/arch/powerpc/include/asm/exception-64e.h index a8b52b61043f..bd8958445336 100644 --- a/arch/powerpc/include/asm/exception-64e.h +++ b/arch/powerpc/include/asm/exception-64e.h @@ -208,5 +208,11 @@ exc_##label##_book3e: ori r3,r3,interrupt_base_book3e@l; \ mtspr SPRN_IVOR##vector_number,r3;
+#define RFI_TO_KERNEL \ + rfi + +#define RFI_TO_USER \ + rfi + #endif /* _ASM_POWERPC_EXCEPTION_64E_H */
diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h index 77f52b26dad6..c8c8a81e3976 100644 --- a/arch/powerpc/include/asm/exception-64s.h +++ b/arch/powerpc/include/asm/exception-64s.h @@ -50,6 +50,35 @@ #define EX_PPR 88 /* SMT thread status register (priority) */ #define EX_CTR 96
+/* Macros for annotating the expected destination of (h)rfid */ + +#define RFI_TO_KERNEL \ + rfid + +#define RFI_TO_USER \ + rfid + +#define RFI_TO_USER_OR_KERNEL \ + rfid + +#define RFI_TO_GUEST \ + rfid + +#define HRFI_TO_KERNEL \ + hrfid + +#define HRFI_TO_USER \ + hrfid + +#define HRFI_TO_USER_OR_KERNEL \ + hrfid + +#define HRFI_TO_GUEST \ + hrfid + +#define HRFI_TO_UNKNOWN \ + hrfid + #ifdef CONFIG_RELOCATABLE #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h) \ ld r12,PACAKBASE(r13); /* get high part of &label */ \