From: Kazuhito Hagio <k-hagio...@nec.com>

Based on Bhupesh's patch and contains Pingfan's idea.

Signed-off-by: Bhupesh Sharma <bhsha...@redhat.com>
Signed-off-by: Kazuhito Hagio <k-hagio...@nec.com>
---
 arch/arm64.c   | 95 ++++++++++++++++++++++++++++++++++++++++++++++++----------
 makedumpfile.c |  2 ++
 makedumpfile.h |  1 +
 3 files changed, 83 insertions(+), 15 deletions(-)

diff --git a/arch/arm64.c b/arch/arm64.c
index 61ec89a..4ece19d 100644
--- a/arch/arm64.c
+++ b/arch/arm64.c
@@ -47,6 +47,8 @@ typedef struct {
 static int lpa_52_bit_support_available;
 static int pgtable_level;
 static int va_bits;
+static int vabits_actual;
+static int flipped_va;
 static unsigned long kimage_voffset;
 
 #define SZ_4K                  4096
@@ -58,7 +60,6 @@ static unsigned long kimage_voffset;
 #define PAGE_OFFSET_42         ((0xffffffffffffffffUL) << 42)
 #define PAGE_OFFSET_47         ((0xffffffffffffffffUL) << 47)
 #define PAGE_OFFSET_48         ((0xffffffffffffffffUL) << 48)
-#define PAGE_OFFSET_52         ((0xffffffffffffffffUL) << 52)
 
 #define pgd_val(x)             ((x).pgd)
 #define pud_val(x)             (pgd_val((x).pgd))
@@ -218,12 +219,20 @@ pmd_page_paddr(pmd_t pmd)
 #define pte_index(vaddr)               (((vaddr) >> PAGESHIFT()) & 
(PTRS_PER_PTE - 1))
 #define pte_offset(dir, vaddr)         (pmd_page_paddr((*dir)) + 
pte_index(vaddr) * sizeof(pte_t))
 
+/*
+ * The linear kernel range starts at the bottom of the virtual address
+ * space. Testing the top bit for the start of the region is a
+ * sufficient check and avoids having to worry about the tag.
+ */
+#define is_linear_addr(addr)   (flipped_va ?   \
+       (!((unsigned long)(addr) & (1UL << (vabits_actual - 1)))) : \
+       (!!((unsigned long)(addr) & (1UL << (vabits_actual - 1)))))
+
 static unsigned long long
 __pa(unsigned long vaddr)
 {
-       if (kimage_voffset == NOT_FOUND_NUMBER ||
-                       (vaddr >= PAGE_OFFSET))
-               return (vaddr - PAGE_OFFSET + info->phys_base);
+       if (kimage_voffset == NOT_FOUND_NUMBER || is_linear_addr(vaddr))
+               return ((vaddr & ~PAGE_OFFSET) + info->phys_base);
        else
                return (vaddr - kimage_voffset);
 }
@@ -253,6 +262,7 @@ static int calculate_plat_config(void)
                        (PAGESIZE() == SZ_64K && va_bits == 42)) {
                pgtable_level = 2;
        } else if ((PAGESIZE() == SZ_64K && va_bits == 48) ||
+                       (PAGESIZE() == SZ_64K && va_bits == 52) ||
                        (PAGESIZE() == SZ_4K && va_bits == 39) ||
                        (PAGESIZE() == SZ_16K && va_bits == 47)) {
                pgtable_level = 3;
@@ -263,6 +273,7 @@ static int calculate_plat_config(void)
                                PAGESIZE(), va_bits);
                return FALSE;
        }
+       DEBUG_MSG("pgtable_level: %d\n", pgtable_level);
 
        return TRUE;
 }
@@ -383,22 +394,54 @@ get_va_bits_from_stext_arm64(void)
        return TRUE;
 }
 
+static void
+get_page_offset_arm64(void)
+{
+       ulong page_end;
+       int vabits_min;
+
+       /*
+        * See arch/arm64/include/asm/memory.h for more details of
+        * the PAGE_OFFSET calculation.
+        */
+       vabits_min = (va_bits > 48) ? 48 : va_bits;
+       page_end = -(1UL << (vabits_min - 1));
+
+       if (SYMBOL(_stext) > page_end) {
+               flipped_va = TRUE;
+               info->page_offset = -(1UL << vabits_actual);
+       } else {
+               flipped_va = FALSE;
+               info->page_offset = -(1UL << (vabits_actual - 1));
+       }
+
+       DEBUG_MSG("page_offset   : %lx (from page_end check)\n",
+               info->page_offset);
+}
+
 int
 get_machdep_info_arm64(void)
 {
+       /* Check if va_bits is still not initialized. If still 0, call
+        * get_versiondep_info() to initialize the same.
+        */
+       if (!va_bits)
+               get_versiondep_info_arm64();
+
        /* Determine if the PA address range is 52-bits: ARMv8.2-LPA */
        if (NUMBER(MAX_PHYSMEM_BITS) != NOT_FOUND_NUMBER) {
                info->max_physmem_bits = NUMBER(MAX_PHYSMEM_BITS);
+               DEBUG_MSG("max_physmem_bits : %ld (vmcoreinfo)\n", 
info->max_physmem_bits);
                if (info->max_physmem_bits == 52)
                        lpa_52_bit_support_available = 1;
-       } else
-               info->max_physmem_bits = 48;
+       } else {
+               if (va_bits == 52)
+                       info->max_physmem_bits = 52; /* just guess */
+               else
+                       info->max_physmem_bits = 48;
 
-       /* Check if va_bits is still not initialized. If still 0, call
-        * get_versiondep_info() to initialize the same.
-        */
-       if (!va_bits)
-               get_versiondep_info_arm64();
+               DEBUG_MSG("max_physmem_bits : %ld (guess)\n", 
info->max_physmem_bits);
+       }
 
        if (!calculate_plat_config()) {
                ERRMSG("Can't determine platform config values\n");
@@ -409,7 +452,6 @@ get_machdep_info_arm64(void)
        info->section_size_bits = SECTIONS_SIZE_BITS;
 
        DEBUG_MSG("kimage_voffset   : %lx\n", kimage_voffset);
-       DEBUG_MSG("max_physmem_bits : %ld\n", info->max_physmem_bits);
        DEBUG_MSG("section_size_bits: %ld\n", info->section_size_bits);
 
        return TRUE;
@@ -444,10 +486,33 @@ get_versiondep_info_arm64(void)
                return FALSE;
        }
 
-       info->page_offset = (0xffffffffffffffffUL) << (va_bits - 1);
+       /*
+        * See TCR_EL1, Translation Control Register (EL1) register
+        * description in the ARMv8 Architecture Reference Manual.
+        * Basically, we can use the TCR_EL1.T1SZ
+        * value to determine the virtual addressing range supported
+        * in the kernel-space (i.e. vabits_actual) since Linux 5.9.
+        */
+       if (NUMBER(TCR_EL1_T1SZ) != NOT_FOUND_NUMBER) {
+               vabits_actual = 64 - NUMBER(TCR_EL1_T1SZ);
+               DEBUG_MSG("vabits_actual : %d (vmcoreinfo)\n", vabits_actual);
+       } else if ((va_bits == 52) && (SYMBOL(mem_section) != 
NOT_FOUND_SYMBOL)) {
+               /*
+                * Linux 5.4 through 5.10 have the following linear space:
+                *  48-bit: 0xffff000000000000 - 0xffff7fffffffffff
+                *  58-bit: 0xfff0000000000000 - 0xfff7ffffffffffff
+                */
+               if (SYMBOL(mem_section) & (1UL << (52 - 1)))
+                       vabits_actual = 48;
+               else
+                       vabits_actual = 52;
+               DEBUG_MSG("vabits_actual : %d (guess from mem_section)\n", 
vabits_actual);
+       } else {
+               vabits_actual = va_bits;
+               DEBUG_MSG("vabits_actual : %d (same as va_bits)\n", 
vabits_actual);
+       }
 
-       DEBUG_MSG("va_bits      : %d\n", va_bits);
-       DEBUG_MSG("page_offset  : %lx\n", info->page_offset);
+       get_page_offset_arm64();
 
        return TRUE;
 }
diff --git a/makedumpfile.c b/makedumpfile.c
index fdfe437..37788ff 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -2396,6 +2396,7 @@ write_vmcoreinfo_data(void)
        WRITE_NUMBER("HUGETLB_PAGE_DTOR", HUGETLB_PAGE_DTOR);
 #ifdef __aarch64__
        WRITE_NUMBER("VA_BITS", VA_BITS);
+       /* WRITE_NUMBER("TCR_EL1_T1SZ", TCR_EL1_T1SZ); should not exists */
        WRITE_NUMBER_UNSIGNED("PHYS_OFFSET", PHYS_OFFSET);
        WRITE_NUMBER_UNSIGNED("kimage_voffset", kimage_voffset);
 #endif
@@ -2838,6 +2839,7 @@ read_vmcoreinfo(void)
        READ_NUMBER("KERNEL_IMAGE_SIZE", KERNEL_IMAGE_SIZE);
 #ifdef __aarch64__
        READ_NUMBER("VA_BITS", VA_BITS);
+       READ_NUMBER("TCR_EL1_T1SZ", TCR_EL1_T1SZ);
        READ_NUMBER_UNSIGNED("PHYS_OFFSET", PHYS_OFFSET);
        READ_NUMBER_UNSIGNED("kimage_voffset", kimage_voffset);
 #endif
diff --git a/makedumpfile.h b/makedumpfile.h
index 5f50080..a151da2 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -1999,6 +1999,7 @@ struct number_table {
        long    KERNEL_IMAGE_SIZE;
 #ifdef __aarch64__
        long    VA_BITS;
+       long    TCR_EL1_T1SZ;
        unsigned long   PHYS_OFFSET;
        unsigned long   kimage_voffset;
 #endif
-- 
2.9.3


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