[coreboot-gerrit] Change in coreboot[master]: arch/x86: Top-align .text in bootblock

[Kyösti Mälkki (Code Review)]

Kyösti Mälkki has submitted this change. ( https://review.coreboot.org/c/coreboot/+/47971 )

Change subject: arch/x86: Top-align .text in bootblock
......................................................................

arch/x86: Top-align .text in bootblock

Move .text section closer to .init. This reduces the size
of the flat bootblock binary and footprint in CBFS.

Change-Id: I64325bd633e1104853cfb928c7f801d94ff3045a
Signed-off-by: Kyösti Mälkki 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47971
Tested-by: build bot (Jenkins) 
Reviewed-by: Arthur Heymans 
---
M src/arch/x86/Kconfig
M src/arch/x86/bootblock.ld
2 files changed, 18 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Arthur Heymans: Looks good to me, approved

diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig
index 4de8c96..943bb91 100644
--- a/src/arch/x86/Kconfig
+++ b/src/arch/x86/Kconfig
@@ -191,6 +191,9 @@
    hex
    default 0x10000

+config FIXED_BOOTBLOCK_SIZE
+	bool
+
 # Default address romstage is to be linked at
 config ROMSTAGE_ADDR
    hex
diff --git a/src/arch/x86/bootblock.ld b/src/arch/x86/bootblock.ld
index 6595262..3cd0900 100644
--- a/src/arch/x86/bootblock.ld
+++ b/src/arch/x86/bootblock.ld
@@ -12,12 +12,25 @@
 #endif

SECTIONS {
+
+#if CONFIG(FIXED_BOOTBLOCK_SIZE)
    . = _ebootblock - CONFIG_C_ENV_BOOTBLOCK_SIZE;
+#else
+	. = BOOTBLOCK_TOP - PROGRAM_SZ;
+	. = ALIGN(16);
+#endif

_bootblock = .;

INCLUDE "bootblock/lib/program.ld"

+	/*
+	 * Allocation reserves extra space here. Alignment requirements
+	 * may cause the total size of a section to change when the start
+	 * address gets applied.
+	 */
+	PROGRAM_SZ = SIZEOF(.text) + 512;
+
    . = MIN(_ID_SECTION, _FIT_POINTER) - EARLYASM_SZ;
    . = CONFIG(SIPI_VECTOR_IN_ROM) ? ALIGN(4096) : ALIGN(16);
    BOOTBLOCK_TOP = .;
@@ -66,3 +79,5 @@
 _bogus1 = ASSERT(_bootblock & 0x80000000, "_bootblock too low, invalid ld script");
 _bogus2 = ASSERT(_start16bit & 0x80000000, "_start16bit too low, invalid ld script");
 _bogus3 = ASSERT(_start16bit >= 0xffff0000, "_start16bit too low. Please report.");
+_bogus4 = ASSERT(_ebootblock - _bootblock <= CONFIG_C_ENV_BOOTBLOCK_SIZE,
+		 "_bootblock too low, increase C_ENV_BOOTBLOCK_SIZE");