mm/kasan: Switch to using __pa_symbol and lm_alias

commit 5c6a84a3 upstream.

__pa_symbol is the correct API to find the physical address of symbols.
Switch to it to allow for debugging APIs to work correctly. Other
functions such as p*d_populate may call __pa internally. Ensure that the
address passed is in the linear region by calling lm_alias.
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: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mm/kasan/kasan_init.c

@@ -15,6 +15,7 @@
 #include <linux/kasan.h>
 #include <linux/kernel.h>
 #include <linux/memblock.h>
+#include <linux/mm.h>
 #include <linux/pfn.h>
 
 #include <asm/page.h>
@@ -49,7 +50,7 @@ static void __init zero_pte_populate(pmd_t *pmd, unsigned long addr,
 	pte_t *pte = pte_offset_kernel(pmd, addr);
 	pte_t zero_pte;
 
-	zero_pte = pfn_pte(PFN_DOWN(__pa(kasan_zero_page)), PAGE_KERNEL);
+	zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_zero_page)), PAGE_KERNEL);
 	zero_pte = pte_wrprotect(zero_pte);
 
 	while (addr + PAGE_SIZE <= end) {
@@ -69,7 +70,7 @@ static void __init zero_pmd_populate(pud_t *pud, unsigned long addr,
 		next = pmd_addr_end(addr, end);
 
 		if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
-			pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
+			pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte));
 			continue;
 		}
 
@@ -92,9 +93,9 @@ static void __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
 		if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
 			pmd_t *pmd;
 
-			pud_populate(&init_mm, pud, kasan_zero_pmd);
+			pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
 			pmd = pmd_offset(pud, addr);
-			pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
+			pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte));
 			continue;
 		}
 
@@ -135,11 +136,11 @@ void __init kasan_populate_zero_shadow(const void *shadow_start,
 			 * puds,pmds, so pgd_populate(), pud_populate()
 			 * is noops.
 			 */
-			pgd_populate(&init_mm, pgd, kasan_zero_pud);
+			pgd_populate(&init_mm, pgd, lm_alias(kasan_zero_pud));
 			pud = pud_offset(pgd, addr);
-			pud_populate(&init_mm, pud, kasan_zero_pmd);
+			pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
 			pmd = pmd_offset(pud, addr);
-			pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
+			pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte));
 			continue;
 		}