git: a194eabe088b - stable/14 - arm64: Use store-pair to zero the kernel bss

The branch stable/14 has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=a194eabe088bcc33ee07eefe3aace2aa3e2a3d25

commit a194eabe088bcc33ee07eefe3aace2aa3e2a3d25
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2024-08-20 17:14:28 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2024-09-02 08:49:38 +0000

    arm64: Use store-pair to zero the kernel bss
    
    While this won't be noticed by most users the time to zero the bss
    while using instruction tracing in the Arm FVP models (simulators) is
    noticeable.
    
    Reduce this time by using a store-pair instruction to double the size
    of memory we zero on each iteration of the loop.
    
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D42733
    
    (cherry picked from commit f1bc3750cf9a6623b0c0861984ef2a8ac966a4e3)
---
 sys/arm64/arm64/locore.S | 2 +-
 sys/conf/ldscript.arm64  | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/sys/arm64/arm64/locore.S b/sys/arm64/arm64/locore.S
index 3db1d3025967..d448f06b2580 100644
--- a/sys/arm64/arm64/locore.S
+++ b/sys/arm64/arm64/locore.S
@@ -109,7 +109,7 @@ virtdone:
 	ldr	x15, .Lbss
 	ldr	x14, .Lend
 1:
-	str	xzr, [x15], #8
+	stp	xzr, xzr, [x15], #16
 	cmp	x15, x14
 	b.lo	1b
 
diff --git a/sys/conf/ldscript.arm64 b/sys/conf/ldscript.arm64
index 185b4485e07a..21c7dc35d9b7 100644
--- a/sys/conf/ldscript.arm64
+++ b/sys/conf/ldscript.arm64
@@ -119,6 +119,7 @@ SECTIONS
   .sdata     : { *(.sdata) }
   _edata  =  .;
   PROVIDE (edata = .);
+  . = ALIGN(16);
   __bss_start = .;
   .sbss      : { *(.sbss) *(.scommon) }
   .bss       :
@@ -126,7 +127,7 @@ SECTIONS
    *(.dynbss)
    *(.bss)
    *(COMMON)
-   . = ALIGN(8);
+   . = ALIGN(16);
    __bss_end = .;
    /* A section for the initial page table, it doesn't need to be in the
       kernel file, however unlike normal .bss entries should not be zeroed