On 9/24/24 12:14, Philippe Mathieu-Daudé wrote:
Hi Peter,
(patch merged as commit 6087df574400659226861fa5ba47970f1fbd277b).
On 12/9/23 16:04, Peter Maydell wrote:
The FEAT_MOPS SETG* instructions are very similar to the SET*
instructions, but as well as setting memory contents they also
set the MTE tags. They are architecturally required to operate
on tag-granule aligned regions only.
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
---
v2: - separate helper functions calling do_setp/setm/sete
- use cpu_st16_mmu()
So you replaced the pair of cpu_stq_mmuidx_ra() from v1 by
cpu_st16_mmu().
---
target/arm/internals.h | 10 ++++
target/arm/tcg/helper-a64.h | 3 ++
target/arm/tcg/a64.decode | 5 ++
target/arm/tcg/helper-a64.c | 86 ++++++++++++++++++++++++++++++++--
target/arm/tcg/mte_helper.c | 40 ++++++++++++++++
target/arm/tcg/translate-a64.c | 20 +++++---
6 files changed, 155 insertions(+), 9 deletions(-)
+/*
+ * Similar, but setting tags. The architecture requires us to do this
+ * in 16-byte chunks. SETP accesses are not tag checked; they set
+ * the tags.
+ */
+static uint64_t set_step_tags(CPUARMState *env, uint64_t toaddr,
+ uint64_t setsize, uint32_t data, int memidx,
+ uint32_t *mtedesc, uintptr_t ra)
+{
+ void *mem;
+ uint64_t cleanaddr;
+
+ setsize = MIN(setsize, page_limit(toaddr));
+
+ cleanaddr = useronly_clean_ptr(toaddr);
+ /*
+ * Trapless lookup: returns NULL for invalid page, I/O,
+ * watchpoints, clean pages, etc.
+ */
+ mem = tlb_vaddr_to_host(env, cleanaddr, MMU_DATA_STORE, memidx);
+
+#ifndef CONFIG_USER_ONLY
+ if (unlikely(!mem)) {
+ /*
+ * Slow-path: just do one write. This will handle the
+ * watchpoint, invalid page, etc handling correctly.
+ * The architecture requires that we do 16 bytes at a time,
+ * and we know both ptr and size are 16 byte aligned.
+ * For clean code pages, the next iteration will see
+ * the page dirty and will use the fast path.
+ */
+ uint64_t repldata = data * 0x0101010101010101ULL;
+ MemOpIdx oi16 = make_memop_idx(MO_TE | MO_128, memidx);
I'm trying to understand the MO_TE use, but I'm not seeing it in
https://developer.arm.com/documentation/ddi0602/2024-06/Base-Instructions/SETGP--SETGM--
SETGE--Memory-set-with-tag-setting-
pseudo code. I also checked
https://developer.arm.com/documentation/ddi0602/2024-06/Shared-Pseudocode/aarch64-
functions-mops?lang=en#impl-aarch64.MemSetBytes.4
and https://developer.arm.com/documentation/ddi0602/2024-06/Shared-Pseudocode/aarch64-
functions-memory?lang=en#AArch64.MemSingleWrite.5
It's not actually needed. All of the bytes stored are identical (see the construction of
repldata).
Removing MO_TE will store the bytes in host byte order, which will avoid an unnecessary
bswap on big-endian hosts.
The stores here are all from
while tagstep > 0 do
tagaddr = memset.toaddress + memset.setsize + (tagstep - 1) * 16;
AArch64.MemTag[tagaddr, accdesc] = tag;
tagstep = tagstep - 1;
r~
