arm64: Update SECTION_SIZE_BITS for kernels >= 5.12

Update the default SECTION_SIZE_BITS value for arm64 Linux 5.12 and later kernels that contain kernel commit f0b13ee23241 ("arm64/sparsemem: reduce SECTION_SIZE_BITS"). Reported-by: Ankur Bansal <[email protected]> Signed-off-by: Kazuhito Hagio <[email protected]>
yangh · Nov 15, 2021 · 8246dce · 8246dce
1 parent 01d20ca
commit 8246dce
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/arm64.c b/arm64.c
@@ -1116,7 +1116,13 @@ arm64_get_section_size_bits(void)
 	int ret;
 	char *string;
 
-	machdep->section_size_bits = _SECTION_SIZE_BITS;
+	if (THIS_KERNEL_VERSION >= LINUX(5,12,0)) {
+		if (machdep->pagesize == 65536)
+			machdep->section_size_bits = _SECTION_SIZE_BITS_5_12_64K;
+		else
+			machdep->section_size_bits = _SECTION_SIZE_BITS_5_12;
+	} else
+		machdep->section_size_bits = _SECTION_SIZE_BITS;
 
 	if ((string = pc->read_vmcoreinfo("NUMBER(SECTION_SIZE_BITS)"))) {
 		machdep->section_size_bits = atol(string);

diff --git a/defs.h b/defs.h
@@ -3261,7 +3261,9 @@ typedef signed int s32;
 #define ARM64_STACK_SIZE   (16384)
 #define ARM64_IRQ_STACK_SIZE   ARM64_STACK_SIZE
 
-#define _SECTION_SIZE_BITS      30
+#define _SECTION_SIZE_BITS           30
+#define _SECTION_SIZE_BITS_5_12      27
+#define _SECTION_SIZE_BITS_5_12_64K  29
 #define _MAX_PHYSMEM_BITS       40
 #define _MAX_PHYSMEM_BITS_3_17  48
 #define _MAX_PHYSMEM_BITS_52    52