qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v6] target/riscv: Add isa extenstion strings to the device tree
@ 2022-03-16 17:57 Atish Patra
  2022-03-17  3:57 ` Bin Meng
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Atish Patra @ 2022-03-16 17:57 UTC (permalink / raw)
  To: qemu-devel
  Cc: qemu-riscv, Heiko Stubner, Anup Patel, Bin Meng, Atish Patra,
	Alistair Francis, Palmer Dabbelt

The Linux kernel parses the ISA extensions from "riscv,isa" DT
property. It used to parse only the single letter base extensions
until now. A generic ISA extension parsing framework was proposed[1]
recently that can parse multi-letter ISA extensions as well.

Generate the extended ISA string by appending the available ISA extensions
to the "riscv,isa" string if it is enabled so that kernel can process it.

[1] https://lkml.org/lkml/2022/2/15/263

Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Suggested-by: Heiko Stubner <heiko@sntech.de>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
Changes from v5->v6:
1. Improved commit message.
2. Fixed a typo for Zfh.

Changes from v4->v5:
1. Fixed the order of Zxx extensions.
2. Added a comment clearly describing the rules of extension order.

Changes from v3->v4:
1. Fixed the order of the extension names.
2. Added all the available ISA extensions in Qemu.

Changes from v2->v3:
1. Used g_strconcat to replace snprintf & a max isa string length as
suggested by Anup.
2. I have not included the Tested-by Tag from Heiko because the
implementation changed from v2 to v3.

Changes from v1->v2:
1. Improved the code redability by using arrays instead of individual check
---
 target/riscv/cpu.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index ddda4906ffb7..937ccdda997b 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -34,6 +34,11 @@
 
 /* RISC-V CPU definitions */
 
+struct isa_ext_data {
+        const char *name;
+        bool enabled;
+};
+
 static const char riscv_exts[26] = "IEMAFDQCLBJTPVNSUHKORWXYZG";
 
 const char * const riscv_int_regnames[] = {
@@ -898,6 +903,60 @@ static void riscv_cpu_class_init(ObjectClass *c, void *data)
     device_class_set_props(dc, riscv_cpu_properties);
 }
 
+#define ISA_EDATA_ENTRY(name, prop) {#name, cpu->cfg.prop}
+
+static void riscv_isa_string_ext(RISCVCPU *cpu, char **isa_str, int max_str_len)
+{
+    char *old = *isa_str;
+    char *new = *isa_str;
+    int i;
+
+    /**
+     * Here are the ordering rules of extension naming defined by RISC-V
+     * specification :
+     * 1. All extensions should be separated from from other multi-letter
+     *    extensions by an underscore.
+     * 2. The first letter following the 'Z' conventionally indicates the most
+     *    closely related alphabetical extension category, IMAFDQLCBKJTPVH.
+     *    If multiple 'Z' extensions are named, they should be ordered first
+     *    by category, then alphabetically within a category.
+     * 3. Standard supervisor-level extensions (starts with 'S') should be
+     *    listed after standard unprivileged extensions.  If multiple
+     *    supervisor-level extensions are listed, they should be ordered
+     *    alphabetically.
+     * 4. Non-standard extensions (starts with 'X') must be listed after all
+     *    standard extensions. They must be separated from other multi-letter
+     *    extensions by an underscore.
+     */
+    struct isa_ext_data isa_edata_arr[] = {
+        ISA_EDATA_ENTRY(zfh, ext_zfh),
+        ISA_EDATA_ENTRY(zfhmin, ext_zfhmin),
+        ISA_EDATA_ENTRY(zfinx, ext_zfinx),
+        ISA_EDATA_ENTRY(zdinx, ext_zdinx),
+        ISA_EDATA_ENTRY(zba, ext_zba),
+        ISA_EDATA_ENTRY(zbb, ext_zbb),
+        ISA_EDATA_ENTRY(zbc, ext_zbc),
+        ISA_EDATA_ENTRY(zbs, ext_zbs),
+        ISA_EDATA_ENTRY(zve32f, ext_zve32f),
+        ISA_EDATA_ENTRY(zve64f, ext_zve64f),
+        ISA_EDATA_ENTRY(zhinx, ext_zhinx),
+        ISA_EDATA_ENTRY(zhinxmin, ext_zhinxmin),
+        ISA_EDATA_ENTRY(svinval, ext_svinval),
+        ISA_EDATA_ENTRY(svnapot, ext_svnapot),
+        ISA_EDATA_ENTRY(svpbmt, ext_svpbmt),
+    };
+
+    for (i = 0; i < ARRAY_SIZE(isa_edata_arr); i++) {
+        if (isa_edata_arr[i].enabled) {
+            new = g_strconcat(old, "_", isa_edata_arr[i].name, NULL);
+            g_free(old);
+            old = new;
+        }
+    }
+
+    *isa_str = new;
+}
+
 char *riscv_isa_string(RISCVCPU *cpu)
 {
     int i;
@@ -910,6 +969,7 @@ char *riscv_isa_string(RISCVCPU *cpu)
         }
     }
     *p = '\0';
+    riscv_isa_string_ext(cpu, &isa_str, maxlen);
     return isa_str;
 }
 
-- 
2.25.1



^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-03-17 10:53 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-03-16 17:57 [PATCH v6] target/riscv: Add isa extenstion strings to the device tree Atish Patra
2022-03-17  3:57 ` Bin Meng
2022-03-17  9:57 ` Frank Chang
2022-03-17 10:50 ` Frank Chang

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).