system/memory: Allow restricting legacy ldst_phys() API usage

Commit 500131154d6 ("exec.c: Add new address_space_ld*/st*
functions") added a new API to fix a shortcoming of the
ld/st*_phys() API, which does blind bus access, not reporting
failure (and it also allow to provide transaction attributes).

Later commit 42874d3a8c6 ("Switch non-CPU callers from ld/st*_phys
to address_space_ld/st*") automatically converted the legacy uses
to the new API, not precising transaction attributes
(MEMTXATTRS_UNSPECIFIED) and ignoring the transation result (passing
NULL pointer as MemTxResult).

While this is a faithful replacement, without any logical change,
we later realized better is to not use MEMTXATTRS_UNSPECIFIED or
NULL MemTxResult, and adapt each call site on a pair basis, looking
at the device model datasheet to do the correct behavior (which is
unlikely to ignore transaction failures).

Since this is quite some work, we defer that to device model
maintainers. Meanwhile we introduce a definition, to allow a
target which removed all legacy API call to prohibit further
legacy API uses, named "TARGET_NOT_USING_LEGACY_LDST_PHYS_API".

Since all targets should be able to check this definition, we
take care to not poison it.

Suggested-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20251224151351.86733-6-philmd@linaro.org>

diff --git a/include/system/memory.h b/include/system/memory.h
index edef51a276dbeb8f0e1c2797ad1a249b41b8d6a5..0e8de527d36f3b262bdd80792926eef77af8fcf2 100644 (file)
--- a/include/system/memory.h
+++ b/include/system/memory.h
@@ -2855,10 +2855,12 @@ MemTxResult address_space_write_rom(AddressSpace *as, hwaddr addr,
 #define ARG1_DECL    AddressSpace *as
 #include "system/memory_ldst.h.inc"
 
+#ifndef TARGET_NOT_USING_LEGACY_LDST_PHYS_API
 #define SUFFIX
 #define ARG1         as
 #define ARG1_DECL    AddressSpace *as
 #include "system/memory_ldst_phys.h.inc"
+#endif
 
 struct MemoryRegionCache {
     uint8_t *ptr;

diff --git a/scripts/make-config-poison.sh b/scripts/make-config-poison.sh
index 2b36907e239310d90ab3a35b448f2a749b99e381..937357b3531baff8b185f0422e1d46cbb2004a02 100755 (executable)
--- a/scripts/make-config-poison.sh
+++ b/scripts/make-config-poison.sh
@@ -10,6 +10,7 @@ exec sed -n \
   -e' /CONFIG_TCG/d' \
   -e '/CONFIG_USER_ONLY/d' \
   -e '/CONFIG_SOFTMMU/d' \
+  -e '/TARGET_NOT_USING_LEGACY_LDST_PHYS_API/d' \
   -e '/^#define / {' \
   -e    's///' \
   -e    's/ .*//' \