[v4.9.y,19/42] mm: Introduce lm_alias

Message ID 20180412111138.40990-20-mark.rutland@arm.com
State New
Headers show
  • arm64 spectre patches
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Commit Message

Mark Rutland April 12, 2018, 11:11 a.m.
From: Laura Abbott <labbott@redhat.com>

commit 568c5fe5a54f2654f5a4c599c45b8a62ed9a2013 upstream.

Certain architectures may have the kernel image mapped separately to
alias the linear map. Introduce a macro lm_alias to translate a kernel
image symbol into its linear alias. This is used in part with work to
add CONFIG_DEBUG_VIRTUAL support for arm64.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Tested-by: Mark Rutland <mark.rutland@arm.com>

Signed-off-by: Laura Abbott <labbott@redhat.com>

Signed-off-by: Will Deacon <will.deacon@arm.com>

Signed-off-by: Mark Rutland <mark.rutland@arm.com> [v4.9 backport]

 include/linux/mm.h | 4 ++++
 1 file changed, 4 insertions(+)



diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8e506783631b..4a07ff4f38e1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -76,6 +76,10 @@  extern int mmap_rnd_compat_bits __read_mostly;
 #define page_to_virt(x)	__va(PFN_PHYS(page_to_pfn(x)))
+#ifndef lm_alias
+#define lm_alias(x)	__va(__pa_symbol(x))
  * To prevent common memory management code establishing
  * a zero page mapping on a read fault.