[PATCH v7 03/12] powerpc: introduce kernstart_virt_addr to store the kernel base

From: Jason Yan
Date: Fri Sep 20 2019 - 05:25:36 EST


Now the kernel base is a fixed value - KERNELBASE. To support KASLR, we
need a variable to store the kernel base.

Signed-off-by: Jason Yan <yanaijie@xxxxxxxxxx>
Cc: Diana Craciun <diana.craciun@xxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxx>
Reviewed-by: Diana Craciun <diana.craciun@xxxxxxx>
Tested-by: Diana Craciun <diana.craciun@xxxxxxx>
---
arch/powerpc/include/asm/page.h | 2 ++
arch/powerpc/mm/init-common.c | 2 ++
2 files changed, 4 insertions(+)

diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 0d52f57fca04..4d32d1b561d6 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -315,6 +315,8 @@ void arch_free_page(struct page *page, int order);

struct vm_area_struct;

+extern unsigned long kernstart_virt_addr;
+
#include <asm-generic/memory_model.h>
#endif /* __ASSEMBLY__ */
#include <asm/slice.h>
diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index e223da482c0c..42ef7a6e6098 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -25,6 +25,8 @@ phys_addr_t memstart_addr __ro_after_init = (phys_addr_t)~0ull;
EXPORT_SYMBOL_GPL(memstart_addr);
phys_addr_t kernstart_addr __ro_after_init;
EXPORT_SYMBOL_GPL(kernstart_addr);
+unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE;
+EXPORT_SYMBOL_GPL(kernstart_virt_addr);

static bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
static bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
--
2.17.2