[PATCH AUTOSEL 4.19 22/36] ARM: add PROC_VTABLE and PROC_TABLE macros

Sasha Levin
2018-11-22T19:52:26Z

From: Russell King <rmk+kernel@armlinux.org.uk>

[ Upstream commit e209950fdd065d2cc46e6338e47e52841b830cba ]

Allow the way we access members of the processor vtable to be changed
at compile time. We will need to move to per-CPU vtables to fix the
Spectre variant 2 issues on big.Little systems.

However, we have a couple of calls that do not need the vtable
treatment, and indeed cause a kernel warning due to the (later) use
of smp_processor_id(), so also introduce the PROC_TABLE macro for
these which always use CPU 0's function pointers.

Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm/include/asm/proc-fns.h | 39 ++++++++++++++++++++++-----------
arch/arm/kernel/setup.c | 4 +---
2 files changed, 27 insertions(+), 16 deletions(-)

diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 30c499146320..c259cc49c641 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -23,7 +23,7 @@ struct mm_struct;
/*
* Don't change this structure - ASM code relies on it.
*/
-extern struct processor {
+struct processor {
/* MISC
* get data abort address/flags
*/
@@ -79,9 +79,13 @@ extern struct processor {
unsigned int suspend_size;
void (*do_suspend)(void *);
void (*do_resume)(void *);
-} processor;
+};

#ifndef MULTI_CPU
+static inline void init_proc_vtable(const struct processor *p)
+{
+}
+
extern void cpu_proc_init(void);
extern void cpu_proc_fin(void);
extern int cpu_do_idle(void);
@@ -98,18 +102,27 @@ extern void cpu_reset(unsigned long addr, bool hvc) __attribute__((noreturn));
extern void cpu_do_suspend(void *);
extern void cpu_do_resume(void *);
#else
-#define cpu_proc_init processor._proc_init
-#define cpu_check_bugs processor.check_bugs
-#define cpu_proc_fin processor._proc_fin
-#define cpu_reset processor.reset
-#define cpu_do_idle processor._do_idle
-#define cpu_dcache_clean_area processor.dcache_clean_area
-#define cpu_set_pte_ext processor.set_pte_ext
-#define cpu_do_switch_mm processor.switch_mm

-/* These three are private to arch/arm/kernel/suspend.c */
-#define cpu_do_suspend processor.do_suspend
-#define cpu_do_resume processor.do_resume
+extern struct processor processor;
+#define PROC_VTABLE(f) processor.f
+#define PROC_TABLE(f) processor.f
+static inline void init_proc_vtable(const struct processor *p)
+{
+ processor = *p;
+}
+
+#define cpu_proc_init PROC_VTABLE(_proc_init)
+#define cpu_check_bugs PROC_VTABLE(check_bugs)
+#define cpu_proc_fin PROC_VTABLE(_proc_fin)
+#define cpu_reset PROC_VTABLE(reset)
+#define cpu_do_idle PROC_VTABLE(_do_idle)
+#define cpu_dcache_clean_area PROC_TABLE(dcache_clean_area)
+#define cpu_set_pte_ext PROC_TABLE(set_pte_ext)
+#define cpu_do_switch_mm PROC_VTABLE(switch_mm)
+
+/* These two are private to arch/arm/kernel/suspend.c */
+#define cpu_do_suspend PROC_VTABLE(do_suspend)
+#define cpu_do_resume PROC_VTABLE(do_resume)
#endif

extern void cpu_resume(void);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 8fd7baa158a4..f269f4440496 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -693,9 +693,7 @@ static void __init setup_processor(void)
cpu_name = list->cpu_name;
__cpu_architecture = __get_cpu_architecture();

-#ifdef MULTI_CPU
- processor = *list->proc;
-#endif
+ init_proc_vtable(list->proc);
#ifdef MULTI_TLB
cpu_tlb = *list->tlb;
#endif
--
2.17.1