From bef444a33004f4062930df1fc703a25dd6d7b460 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Thu, 17 Apr 2014 17:13:26 +0530 Subject: [PATCH] ARC: optimize kernel bss clearing in early boot code using ARC ZOL which reduces tot num of instructions by half Signed-off-by: Vineet Gupta --- arch/arc/kernel/head.S | 7 ++++--- arch/arc/kernel/vmlinux.lds.S | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S index 07a58f2d3077..4d2481bd8b98 100644 --- a/arch/arc/kernel/head.S +++ b/arch/arc/kernel/head.S @@ -77,10 +77,11 @@ stext: ; Clear BSS before updating any globals ; XXX: use ZOL here mov r5, __bss_start - mov r6, __bss_stop + sub r6, __bss_stop, r5 + lsr.f lp_count, r6, 2 + lpnz 1f + st.ab 0, [r5, 4] 1: - st.ab 0, [r5,4] - brlt r5, r6, 1b ; Uboot - kernel ABI ; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2 diff --git a/arch/arc/kernel/vmlinux.lds.S b/arch/arc/kernel/vmlinux.lds.S index 2555f5886af6..dd35bde39f69 100644 --- a/arch/arc/kernel/vmlinux.lds.S +++ b/arch/arc/kernel/vmlinux.lds.S @@ -116,7 +116,7 @@ SECTIONS _edata = .; - BSS_SECTION(0, 0, 0) + BSS_SECTION(4, 4, 4) #ifdef CONFIG_ARC_DW2_UNWIND . = ALIGN(PAGE_SIZE); -- 2.20.1