[U-Boot] [PATCH v2 1/3] efi: Fix truncation of constant value

* [U-Boot] [PATCH v2 1/3] efi: Fix truncation of constant value
@ 2018-07-14 20:53 Eugeniu Rosca
  2018-07-14 20:53 ` [U-Boot] [PATCH v2 2/3] efi: Add EFI_MEMORY_{NV, MORE_RELIABLE, RO} attributes Eugeniu Rosca
                   ` (3 more replies)
  0 siblings, 4 replies; 16+ messages in thread
From: Eugeniu Rosca @ 2018-07-14 20:53 UTC (permalink / raw)
  To: u-boot

Starting with commit 867a6ac86dd8 ("efi: Add start-up library code"),
sparse constantly complains about truncated constant value in efi.h:

include/efi.h:176:35: warning: cast truncates bits from constant value (8000000000000000 becomes 0)

This can get quite noisy, preventing real issues to be noticed:

$ make defconfig
*** Default configuration is based on 'sandbox_defconfig'
$ make C=2 -j12 2>&1 | grep truncates | wc -l
441

After the patch is applied:
$ make C=2 -j12 2>&1 | grep truncates | wc -l
0
$ sparse --version
v0.5.2

Following the suggestion of Heinrich Schuchardt, instead of only
fixing the root-cause, I replaced the whole enum of _SHIFT values
by ULL defines. This matches both the UEFI 2.7 spec and the Linux
kernel implementation.

Some ELF size comparison before and after the patch (gcc 7.3.0):

efi-x86_payload64_defconfig:
text    data    bss     dec       hex   filename
407174  29432   278676  715282    aea12 u-boot.old
407152  29464   278676  715292    aea1c u-boot.new
-22     +32     0       +10

efi-x86_payload32_defconfig:
text    data    bss     dec       hex   filename
447075  30308   280076  757459    b8ed3 u-boot.old
447053  30340   280076  757469    b8edd u-boot.new
-22     +32     0       +10

Fixes: 867a6ac86dd8 ("efi: Add start-up library code")
Suggested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
---

v2:
- Replace _SHIFT enum values by ULL defines to match UEFI 2.7 spec
- Add ELF size comparison to patch description

 cmd/efi.c                   | 22 +++++++++++-----------
 include/efi.h               | 24 ++++++++++--------------
 lib/efi_loader/efi_memory.c |  7 +++----
 3 files changed, 24 insertions(+), 29 deletions(-)

diff --git a/cmd/efi.c b/cmd/efi.c
index 6c1eb88424be..92a565f71373 100644
--- a/cmd/efi.c
+++ b/cmd/efi.c
@@ -28,18 +28,18 @@ static const char *const type_name[] = {
 };
 
 static struct attr_info {
-	int shift;
+	u64 val;
 	const char *name;
 } mem_attr[] = {
-	{ EFI_MEMORY_UC_SHIFT, "uncached" },
-	{ EFI_MEMORY_WC_SHIFT, "write-coalescing" },
-	{ EFI_MEMORY_WT_SHIFT, "write-through" },
-	{ EFI_MEMORY_WB_SHIFT, "write-back" },
-	{ EFI_MEMORY_UCE_SHIFT, "uncached & exported" },
-	{ EFI_MEMORY_WP_SHIFT, "write-protect" },
-	{ EFI_MEMORY_RP_SHIFT, "read-protect" },
-	{ EFI_MEMORY_XP_SHIFT, "execute-protect" },
-	{ EFI_MEMORY_RUNTIME_SHIFT, "needs runtime mapping" }
+	{ EFI_MEMORY_UC, "uncached" },
+	{ EFI_MEMORY_WC, "write-coalescing" },
+	{ EFI_MEMORY_WT, "write-through" },
+	{ EFI_MEMORY_WB, "write-back" },
+	{ EFI_MEMORY_UCE, "uncached & exported" },
+	{ EFI_MEMORY_WP, "write-protect" },
+	{ EFI_MEMORY_RP, "read-protect" },
+	{ EFI_MEMORY_XP, "execute-protect" },
+	{ EFI_MEMORY_RUNTIME, "needs runtime mapping" }
 };
 
 /* Maximum different attribute values we can track */
@@ -173,7 +173,7 @@ static void efi_print_mem_table(struct efi_entry_memmap *map,
 		printf("%c%llx: ", attr & EFI_MEMORY_RUNTIME ? 'r' : ' ',
 		       attr & ~EFI_MEMORY_RUNTIME);
 		for (j = 0, first = true; j < ARRAY_SIZE(mem_attr); j++) {
-			if (attr & (1ULL << mem_attr[j].shift)) {
+			if (attr & mem_attr[j].val) {
 				if (first)
 					first = false;
 				else
diff --git a/include/efi.h b/include/efi.h
index 0fe15e65c06c..eb2a569fe010 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -162,20 +162,16 @@ enum efi_mem_type {
 };
 
 /* Attribute values */
-enum {
-	EFI_MEMORY_UC_SHIFT	= 0,	/* uncached */
-	EFI_MEMORY_WC_SHIFT	= 1,	/* write-coalescing */
-	EFI_MEMORY_WT_SHIFT	= 2,	/* write-through */
-	EFI_MEMORY_WB_SHIFT	= 3,	/* write-back */
-	EFI_MEMORY_UCE_SHIFT	= 4,	/* uncached, exported */
-	EFI_MEMORY_WP_SHIFT	= 12,	/* write-protect */
-	EFI_MEMORY_RP_SHIFT	= 13,	/* read-protect */
-	EFI_MEMORY_XP_SHIFT	= 14,	/* execute-protect */
-	EFI_MEMORY_RUNTIME_SHIFT = 63,	/* range requires runtime mapping */
-
-	EFI_MEMORY_RUNTIME = 1ULL << EFI_MEMORY_RUNTIME_SHIFT,
-	EFI_MEM_DESC_VERSION	= 1,
-};
+#define EFI_MEMORY_UC		((u64)0x0000000000000001ULL)	/* uncached */
+#define EFI_MEMORY_WC		((u64)0x0000000000000002ULL)	/* write-coalescing */
+#define EFI_MEMORY_WT		((u64)0x0000000000000004ULL)	/* write-through */
+#define EFI_MEMORY_WB		((u64)0x0000000000000008ULL)	/* write-back */
+#define EFI_MEMORY_UCE		((u64)0x0000000000000010ULL)	/* uncached, exported */
+#define EFI_MEMORY_WP		((u64)0x0000000000001000ULL)	/* write-protect */
+#define EFI_MEMORY_RP		((u64)0x0000000000002000ULL)	/* read-protect */
+#define EFI_MEMORY_XP		((u64)0x0000000000004000ULL)	/* execute-protect */
+#define EFI_MEMORY_RUNTIME	((u64)0x8000000000000000ULL)	/* range requires runtime mapping */
+#define EFI_MEM_DESC_VERSION	1
 
 #define EFI_PAGE_SHIFT		12
 #define EFI_PAGE_SIZE		(1UL << EFI_PAGE_SHIFT)
diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
index ec66af98ea8f..233333bf6b18 100644
--- a/lib/efi_loader/efi_memory.c
+++ b/lib/efi_loader/efi_memory.c
@@ -171,14 +171,13 @@ uint64_t efi_add_memory_map(uint64_t start, uint64_t pages, int memory_type,
 	switch (memory_type) {
 	case EFI_RUNTIME_SERVICES_CODE:
 	case EFI_RUNTIME_SERVICES_DATA:
-		newlist->desc.attribute = (1 << EFI_MEMORY_WB_SHIFT) |
-					  (1ULL << EFI_MEMORY_RUNTIME_SHIFT);
+		newlist->desc.attribute = EFI_MEMORY_WB | EFI_MEMORY_RUNTIME;
 		break;
 	case EFI_MMAP_IO:
-		newlist->desc.attribute = 1ULL << EFI_MEMORY_RUNTIME_SHIFT;
+		newlist->desc.attribute = EFI_MEMORY_RUNTIME;
 		break;
 	default:
-		newlist->desc.attribute = 1 << EFI_MEMORY_WB_SHIFT;
+		newlist->desc.attribute = EFI_MEMORY_WB;
 		break;
 	}
 
-- 
2.18.0

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