xz: Add ARM64 BCJ filter

Also omit a duplicated check for XZ_DEC_ARM in xz_private.h.

A later commit updates lib/decompress_unxz.c to enable this filter for
kernel decompression.  lib/decompress_unxz.c is already used if
CONFIG_EFI_ZBOOT=y && CONFIG_KERNEL_XZ=y.

This filter can be used by Squashfs without modifications to the Squashfs
kernel code (only needs support in userspace Squashfs-tools).

Link: https://lkml.kernel.org/r/20240721133633.47721-12-lasse.collin@tukaani.org
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Reviewed-by: Sam James <sam@gentoo.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jubin Zhong <zhongjubin@huawei.com>
Cc: Jules Maselbas <jmaselbas@zdiv.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rui Li <me@lirui.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/xz/Kconfig b/lib/xz/Kconfig
index 6b80453d8f540090188f971f298ddc61475dd0ff..1166627a87dc5fd397fb61220264fa32e5c359ae 100644 (file)
--- a/lib/xz/Kconfig
+++ b/lib/xz/Kconfig
@@ -30,6 +30,11 @@ config XZ_DEC_ARMTHUMB
        default y
        select XZ_DEC_BCJ
 
+config XZ_DEC_ARM64
+       bool "ARM64 BCJ filter decoder" if EXPERT
+       default y
+       select XZ_DEC_BCJ
+
 config XZ_DEC_SPARC
        bool "SPARC BCJ filter decoder" if EXPERT
        default y

diff --git a/lib/xz/xz_dec_bcj.c b/lib/xz/xz_dec_bcj.c
index e0b4bf4999c003a96a11c52f04f31199b2a99dd4..941198a8a55b75faa09ad0b7f349b2f7bb1be211 100644 (file)
--- a/lib/xz/xz_dec_bcj.c
+++ b/lib/xz/xz_dec_bcj.c
@@ -23,7 +23,8 @@ struct xz_dec_bcj {
                BCJ_IA64 = 6,       /* Big or little endian */
                BCJ_ARM = 7,        /* Little endian only */
                BCJ_ARMTHUMB = 8,   /* Little endian only */
-               BCJ_SPARC = 9       /* Big or little endian */
+               BCJ_SPARC = 9,      /* Big or little endian */
+               BCJ_ARM64 = 10      /* AArch64 */
        } type;
 
        /*
@@ -346,6 +347,47 @@ static size_t bcj_sparc(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
 }
 #endif
 
+#ifdef XZ_DEC_ARM64
+static size_t bcj_arm64(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
+{
+       size_t i;
+       uint32_t instr;
+       uint32_t addr;
+
+       size &= ~(size_t)3;
+
+       for (i = 0; i < size; i += 4) {
+               instr = get_unaligned_le32(buf + i);
+
+               if ((instr >> 26) == 0x25) {
+                       /* BL instruction */
+                       addr = instr - ((s->pos + (uint32_t)i) >> 2);
+                       instr = 0x94000000 | (addr & 0x03FFFFFF);
+                       put_unaligned_le32(instr, buf + i);
+
+               } else if ((instr & 0x9F000000) == 0x90000000) {
+                       /* ADRP instruction */
+                       addr = ((instr >> 29) & 3) | ((instr >> 3) & 0x1FFFFC);
+
+                       /* Only convert values in the range +/-512 MiB. */
+                       if ((addr + 0x020000) & 0x1C0000)
+                               continue;
+
+                       addr -= (s->pos + (uint32_t)i) >> 12;
+
+                       instr &= 0x9000001F;
+                       instr |= (addr & 3) << 29;
+                       instr |= (addr & 0x03FFFC) << 3;
+                       instr |= (0U - (addr & 0x020000)) & 0xE00000;
+
+                       put_unaligned_le32(instr, buf + i);
+               }
+       }
+
+       return i;
+}
+#endif
+
 /*
  * Apply the selected BCJ filter. Update *pos and s->pos to match the amount
  * of data that got filtered.
@@ -392,6 +434,11 @@ static void bcj_apply(struct xz_dec_bcj *s,
        case BCJ_SPARC:
                filtered = bcj_sparc(s, buf, size);
                break;
+#endif
+#ifdef XZ_DEC_ARM64
+       case BCJ_ARM64:
+               filtered = bcj_arm64(s, buf, size);
+               break;
 #endif
        default:
                /* Never reached but silence compiler warnings. */
@@ -565,6 +612,9 @@ XZ_EXTERN enum xz_ret xz_dec_bcj_reset(struct xz_dec_bcj *s, uint8_t id)
 #endif
 #ifdef XZ_DEC_SPARC
        case BCJ_SPARC:
+#endif
+#ifdef XZ_DEC_ARM64
+       case BCJ_ARM64:
 #endif
                break;
 

diff --git a/lib/xz/xz_private.h b/lib/xz/xz_private.h
index 811add814ae4cdb7ac9fc885b43ed1b9c3dbacf8..307e0de8c2604a7f69dce22dfe52d357665c2562 100644 (file)
--- a/lib/xz/xz_private.h
+++ b/lib/xz/xz_private.h
@@ -36,6 +36,9 @@
 #              ifdef CONFIG_XZ_DEC_SPARC
 #                      define XZ_DEC_SPARC
 #              endif
+#              ifdef CONFIG_XZ_DEC_ARM64
+#                      define XZ_DEC_ARM64
+#              endif
 #              ifdef CONFIG_XZ_DEC_MICROLZMA
 #                      define XZ_DEC_MICROLZMA
 #              endif
@@ -97,9 +100,9 @@
  */
 #ifndef XZ_DEC_BCJ
 #      if defined(XZ_DEC_X86) || defined(XZ_DEC_POWERPC) \
-                       || defined(XZ_DEC_IA64) || defined(XZ_DEC_ARM) \
+                       || defined(XZ_DEC_IA64) \
                        || defined(XZ_DEC_ARM) || defined(XZ_DEC_ARMTHUMB) \
-                       || defined(XZ_DEC_SPARC)
+                       || defined(XZ_DEC_SPARC) || defined(XZ_DEC_ARM64)
 #              define XZ_DEC_BCJ
 #      endif
 #endif