diff mbox series

[v4,17/75] x86/boot/compressed/64: Change add_identity_map() to take start and end

Message ID 20200714120917.11253-18-joro@8bytes.org (mailing list archive)
State New, archived
Headers show
Series x86: SEV-ES Guest Support | expand

Commit Message

Joerg Roedel July 14, 2020, 12:08 p.m. UTC 
From: Joerg Roedel <jroedel@suse.de>

Changing the function to take start and end as parameters instead of
start and size simplifies the callers, which don't need to calculate
the size if they already have start and end.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/boot/compressed/ident_map_64.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

Comments

Kees Cook July 15, 2020, 1:24 a.m. UTC | #1 
On Tue, Jul 14, 2020 at 02:08:19PM +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> Changing the function to take start and end as parameters instead of
> start and size simplifies the callers, which don't need to calculate
> the size if they already have start and end.
> 
> Signed-off-by: Joerg Roedel <jroedel@suse.de>

Reviewed-by: Kees Cook <keescook@chromium.org>
diff mbox series

Patch

diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
index c63257bf8373..62e42c11a336 100644
--- a/arch/x86/boot/compressed/ident_map_64.c
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -89,10 +89,8 @@  static struct x86_mapping_info mapping_info;
 /*
  * Adds the specified range to the identity mappings.
  */
-static void add_identity_map(unsigned long start, unsigned long size)
+static void add_identity_map(unsigned long start, unsigned long end)
 {
-	unsigned long end = start + size;
-
 	/* Align boundary to 2M. */
 	start = round_down(start, PMD_SIZE);
 	end = round_up(end, PMD_SIZE);
@@ -107,8 +105,6 @@  static void add_identity_map(unsigned long start, unsigned long size)
 /* Locates and clears a region for a new top level page table. */
 void initialize_identity_maps(void)
 {
-	unsigned long start, size;
-
 	/* If running as an SEV guest, the encryption mask is required. */
 	set_sev_encryption_mask();
 
@@ -155,9 +151,7 @@  void initialize_identity_maps(void)
 	 * New page-table is set up - map the kernel image and load it
 	 * into cr3.
 	 */
-	start = (unsigned long)_head;
-	size  = _end - _head;
-	add_identity_map(start, size);
+	add_identity_map((unsigned long)_head, (unsigned long)_end);
 	write_cr3(top_level_pgt);
 }
 
@@ -189,7 +183,8 @@  static void do_pf_error(const char *msg, unsigned long error_code,
 
 void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
-	unsigned long address = native_read_cr2();
+	unsigned long address = native_read_cr2() & PMD_MASK;
+	unsigned long end = address + PMD_SIZE;
 
 	/*
 	 * Check for unexpected error codes. Unexpected are:
@@ -204,5 +199,5 @@  void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code)
 	 * Error code is sane - now identity map the 2M region around
 	 * the faulting address.
 	 */
-	add_identity_map(address & PMD_MASK, PMD_SIZE);
+	add_identity_map(address, end);
 }