diff options
| author | Tom Rini <trini@konsulko.com> | 2020-12-10 21:27:36 -0500 |
|---|---|---|
| committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2021-12-14 16:00:44 +0100 |
| commit | 03b601aff130616e730ac81cc6f448f2bd2bc192 (patch) | |
| tree | d4fd30ccce44bed3255bae12301ecf0fd03a8787 /cpukit/include/libfdt.h | |
| parent | libfdt: Check for 8-byte address alignment in fdt_ro_probe_() (diff) | |
| download | rtems-03b601aff130616e730ac81cc6f448f2bd2bc192.tar.bz2 | |
libfdt: Internally perform potentially unaligned loads
Commits 6dcb8ba4 "libfdt: Add helpers for accessing unaligned words"
introduced changes to support unaligned reads for ARM platforms and
11738cf01f15 "libfdt: Don't use memcpy to handle unaligned reads on ARM"
improved the performance of these helpers.
On further discussion, while there are potential cases where we could be
used on platforms that do not fixup unaligned reads for us, making this
choice the default is very expensive in terms of binary size and access
time. To address this, introduce and use new fdt{32,64}_ld_ functions
that call fdt{32,64}_to_cpu() as was done prior to the above mentioned
commits. Leave the existing load functions as unaligned-safe and
include comments in both cases.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
Message-Id: <20201211022736.31657-1-trini@konsulko.com>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to '')
| -rw-r--r-- | cpukit/include/libfdt.h | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/cpukit/include/libfdt.h b/cpukit/include/libfdt.h index 89adee3cd7..2bc16a8b3f 100644 --- a/cpukit/include/libfdt.h +++ b/cpukit/include/libfdt.h @@ -126,12 +126,10 @@ static inline void *fdt_offset_ptr_w(void *fdt, int offset, int checklen) uint32_t fdt_next_tag(const void *fdt, int offset, int *nextoffset); /* - * Alignment helpers: - * These helpers access words from a device tree blob. They're - * built to work even with unaligned pointers on platforms (ike - * ARM) that don't like unaligned loads and stores + * External helpers to access words from a device tree blob. They're built + * to work even with unaligned pointers on platforms (such as ARMv5) that don't + * like unaligned loads and stores. */ - static inline uint32_t fdt32_ld(const fdt32_t *p) { const uint8_t *bp = (const uint8_t *)p; |