From: Tom Rini <trini-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
To: devicetree-compiler-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: David Gibson
<david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>,
Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Subject: [PATCH] libfdt: Default to assuming aligned reads are OK
Date: Fri, 30 Oct 2020 14:56:58 -0400 [thread overview]
Message-ID: <20201030185658.4655-1-trini@konsulko.com> (raw)
Start with commit 6dcb8ba4 "libfdt: Add helpers for accessing unaligned
words" which introduced changes to support unaligned reads for ARM
platforms and 11738cf01f15 "libfdt: Don't use memcpy to handle unaligned
reads on ARM" to improve the performance of these helpers, libfdt has
defaulted to assuming that unaligned memory access could be a fatal
problem.
Upon further discussion on the mailing list, we leave the improved
unaligned-safe memory load functions available if needed, but go back to
using fdt{32,64}_to_cpu() for access as generally platforms handle
unaligned access safely and there is still a sizable performance and
size impact of using the always-safe helpers in all cases.
Signed-off-by: Tom Rini <trini-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
---
fdtget.c | 2 +-
libfdt/fdt_ro.c | 20 ++++++++++----------
libfdt/libfdt.h | 2 +-
3 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/fdtget.c b/fdtget.c
index 777582e2d45f..7cee28718cbc 100644
--- a/fdtget.c
+++ b/fdtget.c
@@ -62,7 +62,7 @@ static int show_cell_list(struct display_info *disp, const char *data, int len,
for (i = 0; i < len; i += size, p += size) {
if (i)
printf(" ");
- value = size == 4 ? fdt32_ld((const fdt32_t *)p) :
+ value = size == 4 ? fdt32_to_cpu(*(const fdt32_t *)p) :
size == 2 ? (*p << 8) | p[1] : *p;
printf(fmt, value);
}
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index 91cc6fefe374..5bc27ac97317 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -181,8 +181,8 @@ int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
if (!can_assume(VALID_INPUT) && !re)
return -FDT_ERR_BADOFFSET;
- *address = fdt64_ld(&re->address);
- *size = fdt64_ld(&re->size);
+ *address = fdt64_to_cpu(re->address);
+ *size = fdt64_to_cpu(re->size);
return 0;
}
@@ -192,7 +192,7 @@ int fdt_num_mem_rsv(const void *fdt)
const struct fdt_reserve_entry *re;
for (i = 0; (re = fdt_mem_rsv(fdt, i)) != NULL; i++) {
- if (fdt64_ld(&re->size) == 0)
+ if (fdt64_to_cpu(re->size) == 0)
return i;
}
return -FDT_ERR_TRUNCATED;
@@ -370,7 +370,7 @@ static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt,
prop = fdt_offset_ptr_(fdt, offset);
if (lenp)
- *lenp = fdt32_ld(&prop->len);
+ *lenp = fdt32_to_cpu(prop->len);
return prop;
}
@@ -408,7 +408,7 @@ static const struct fdt_property *fdt_get_property_namelen_(const void *fdt,
offset = -FDT_ERR_INTERNAL;
break;
}
- if (fdt_string_eq_(fdt, fdt32_ld(&prop->nameoff),
+ if (fdt_string_eq_(fdt, fdt32_to_cpu(prop->nameoff),
name, namelen)) {
if (poffset)
*poffset = offset;
@@ -461,7 +461,7 @@ const void *fdt_getprop_namelen(const void *fdt, int nodeoffset,
/* Handle realignment */
if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
- (poffset + sizeof(*prop)) % 8 && fdt32_ld(&prop->len) >= 8)
+ (poffset + sizeof(*prop)) % 8 && fdt32_to_cpu(prop->len) >= 8)
return prop->data + 4;
return prop->data;
}
@@ -479,7 +479,7 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset,
int namelen;
if (!can_assume(VALID_INPUT)) {
- name = fdt_get_string(fdt, fdt32_ld(&prop->nameoff),
+ name = fdt_get_string(fdt, fdt32_to_cpu(prop->nameoff),
&namelen);
if (!name) {
if (lenp)
@@ -488,13 +488,13 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset,
}
*namep = name;
} else {
- *namep = fdt_string(fdt, fdt32_ld(&prop->nameoff));
+ *namep = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
}
}
/* Handle realignment */
if (!can_assume(LATEST) && fdt_version(fdt) < 0x10 &&
- (offset + sizeof(*prop)) % 8 && fdt32_ld(&prop->len) >= 8)
+ (offset + sizeof(*prop)) % 8 && fdt32_to_cpu(prop->len) >= 8)
return prop->data + 4;
return prop->data;
}
@@ -519,7 +519,7 @@ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
return 0;
}
- return fdt32_ld(php);
+ return fdt32_to_cpu(*php);
}
const char *fdt_get_alias_namelen(const void *fdt,
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index 544d3efff584..5004300e7ddc 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -236,7 +236,7 @@ int fdt_next_subnode(const void *fdt, int offset);
/* General functions */
/**********************************************************************/
#define fdt_get_header(fdt, field) \
- (fdt32_ld(&((const struct fdt_header *)(fdt))->field))
+ (fdt32_to_cpu(((const struct fdt_header *)(fdt))->field))
#define fdt_magic(fdt) (fdt_get_header(fdt, magic))
#define fdt_totalsize(fdt) (fdt_get_header(fdt, totalsize))
#define fdt_off_dt_struct(fdt) (fdt_get_header(fdt, off_dt_struct))
--
2.17.1
next reply other threads:[~2020-10-30 18:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-30 18:56 Tom Rini [this message]
[not found] ` <20201030185658.4655-1-trini-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
2020-11-02 0:56 ` [PATCH] libfdt: Default to assuming aligned reads are OK David Gibson
[not found] ` <20201102005607.GA143651-l+x2Y8Cxqc4e6aEkudXLsA@public.gmane.org>
2020-11-02 16:03 ` Tom Rini
2020-11-04 2:44 ` David Gibson
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