From 24f60011fd43683d8e3916435c4c726e9baac9c9 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 23 Feb 2024 15:36:00 +1100 Subject: [PATCH] libfdt: Simplify adjustment of values for local fixups In a couple of places in fdt_overlay.c we need to adjust a phandle value in a property (either a node's phandle itself or a reference) by some delta. Currently this is done if a fairly convoluted way, open-coding loading the value and handling of a non-aligned reference, and then using fdt_setprop_inplace_partial() to replace the value. This becomes much simpler if we use fdt_getprop_w() to get a writable pointer to the value then we can just load/store it with fdt32_{ld,st}(). Signed-off-by: David Gibson --- libfdt/fdt_overlay.c | 52 +++++++++++++------------------------------- 1 file changed, 15 insertions(+), 37 deletions(-) diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c index 5c0c398..7ec839a 100644 --- a/libfdt/fdt_overlay.c +++ b/libfdt/fdt_overlay.c @@ -101,26 +101,22 @@ int fdt_overlay_target_offset(const void *fdt, const void *fdto, static int overlay_phandle_add_offset(void *fdt, int node, const char *name, uint32_t delta) { - const fdt32_t *val; - uint32_t adj_val; + fdt32_t *valp, val; int len; - val = fdt_getprop(fdt, node, name, &len); - if (!val) + valp = fdt_getprop_w(fdt, node, name, &len); + if (!valp) return len; - if (len != sizeof(*val)) + if (len != sizeof(val)) return -FDT_ERR_BADPHANDLE; - adj_val = fdt32_to_cpu(*val); - if ((adj_val + delta) < adj_val) - return -FDT_ERR_NOPHANDLES; - - adj_val += delta; - if (adj_val == (uint32_t)-1) + val = fdt32_ld(valp); + if (val + delta < val || val + delta == (uint32_t)-1) return -FDT_ERR_NOPHANDLES; - return fdt_setprop_inplace_u32(fdt, node, name, adj_val); + fdt32_st(valp, val + delta); + return 0; } /** @@ -213,8 +209,8 @@ static int overlay_update_local_node_references(void *fdto, fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) { const fdt32_t *fixup_val; - const char *tree_val; const char *name; + char *tree_val; int fixup_len; int tree_len; int i; @@ -228,7 +224,7 @@ static int overlay_update_local_node_references(void *fdto, return -FDT_ERR_BADOVERLAY; fixup_len /= sizeof(uint32_t); - tree_val = fdt_getprop(fdto, tree_node, name, &tree_len); + tree_val = fdt_getprop_w(fdto, tree_node, name, &tree_len); if (!tree_val) { if (tree_len == -FDT_ERR_NOTFOUND) return -FDT_ERR_BADOVERLAY; @@ -237,33 +233,15 @@ static int overlay_update_local_node_references(void *fdto, } for (i = 0; i < fixup_len; i++) { - fdt32_t adj_val; - uint32_t poffset; + fdt32_t *refp; - poffset = fdt32_to_cpu(fixup_val[i]); + refp = (fdt32_t *)(tree_val + fdt32_ld_(fixup_val + i)); /* - * phandles to fixup can be unaligned. - * - * Use a memcpy for the architectures that do - * not support unaligned accesses. + * phandles to fixup can be unaligned, so use + * fdt32_{ld,st}() to read/write them. */ - memcpy(&adj_val, tree_val + poffset, sizeof(adj_val)); - - adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta); - - ret = fdt_setprop_inplace_namelen_partial(fdto, - tree_node, - name, - strlen(name), - poffset, - &adj_val, - sizeof(adj_val)); - if (ret == -FDT_ERR_NOSPACE) - return -FDT_ERR_BADOVERLAY; - - if (ret) - return ret; + fdt32_st(refp, fdt32_ld(refp) + delta); } }