scontext size is 16 bits on RV32 and 32 bits on RV64, as recommended by
version 1.0 2025-02-21 of the debug specification.
When the Smstateen extension is implemented, accessibility to the
scontext CSR is controlled by bit 57 of the [mh]stateen0 CSRs.
Signed-off-by: Florian Lugou <florian.lugou@provenrun.com>
---
target/riscv/cpu.h | 1 +
target/riscv/cpu_bits.h | 5 +++++
target/riscv/csr.c | 36 ++++++++++++++++++++++++++++++++++++
target/riscv/debug.c | 1 +
4 files changed, 43 insertions(+)
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 97713681cb..e47200f409 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -430,6 +430,7 @@ struct CPUArchState {
target_ulong tdata2[RV_MAX_TRIGGERS];
target_ulong tdata3[RV_MAX_TRIGGERS];
target_ulong mcontext;
+ target_ulong scontext;
struct CPUBreakpoint *cpu_breakpoint[RV_MAX_TRIGGERS];
struct CPUWatchpoint *cpu_watchpoint[RV_MAX_TRIGGERS];
QEMUTimer *itrigger_timer[RV_MAX_TRIGGERS];
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index f97c48a394..add0bb9d0e 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -247,6 +247,9 @@
#define CSR_SIEH 0x114
#define CSR_SIPH 0x154
+/* Supervisor-Level Sdtrig CSRs (debug) */
+#define CSR_SCONTEXT 0x5a8
+
/* Hpervisor CSRs */
#define CSR_HSTATUS 0x600
#define CSR_HEDELEG 0x602
@@ -959,4 +962,6 @@ typedef enum RISCVException {
#define MCONTEXT64 0x0000000000001FFFULL
#define MCONTEXT32_HCONTEXT 0x0000007F
#define MCONTEXT64_HCONTEXT 0x0000000000003FFFULL
+#define SCONTEXT32 0x0000FFFF
+#define SCONTEXT64 0x00000000FFFFFFFFULL
#endif
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index afb7544f07..1c1ac8ed67 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -3221,6 +3221,10 @@ static RISCVException write_mstateen0(CPURISCVState *env, int csrno,
wr_mask |= SMSTATEEN0_P1P13;
}
+ if (riscv_cpu_cfg(env)->debug) {
+ wr_mask |= SMSTATEEN0_HSCONTXT;
+ }
+
if (riscv_cpu_cfg(env)->ext_smaia || riscv_cpu_cfg(env)->ext_smcsrind) {
wr_mask |= SMSTATEEN0_SVSLCT;
}
@@ -5053,6 +5057,35 @@ static RISCVException write_mcontext(CPURISCVState *env, int csrno,
return RISCV_EXCP_NONE;
}
+static RISCVException read_scontext(CPURISCVState *env, int csrno,
+ target_ulong *val)
+{
+ RISCVException ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSCONTXT);
+ if (ret != RISCV_EXCP_NONE) {
+ return ret;
+ }
+
+ *val = env->scontext;
+ return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_scontext(CPURISCVState *env, int csrno,
+ target_ulong val)
+{
+ bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;
+
+ RISCVException ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSCONTXT);
+ if (ret != RISCV_EXCP_NONE) {
+ return ret;
+ }
+
+ /* Spec suggest 16-bit for RV32 and 34-bit for RV64 */
+ target_ulong mask = rv32 ? SCONTEXT32 : SCONTEXT64;
+
+ env->scontext = val & mask;
+ return RISCV_EXCP_NONE;
+}
+
static RISCVException read_mnscratch(CPURISCVState *env, int csrno,
target_ulong *val)
{
@@ -5705,6 +5738,9 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
[CSR_SIEH] = { "sieh", aia_smode32, NULL, NULL, rmw_sieh },
[CSR_SIPH] = { "siph", aia_smode32, NULL, NULL, rmw_siph },
+ /* Supervisor-Level Sdtrig CSRs (debug) */
+ [CSR_SCONTEXT] = { "scontext", debug, read_scontext, write_scontext },
+
[CSR_HSTATUS] = { "hstatus", hmode, read_hstatus, write_hstatus,
.min_priv_ver = PRIV_VERSION_1_12_0 },
[CSR_HEDELEG] = { "hedeleg", hmode, read_hedeleg, write_hedeleg,
diff --git a/target/riscv/debug.c b/target/riscv/debug.c
index f6241a80be..914a9ce0f8 100644
--- a/target/riscv/debug.c
+++ b/target/riscv/debug.c
@@ -1086,4 +1086,5 @@ void riscv_trigger_reset_hold(CPURISCVState *env)
}
env->mcontext = 0;
+ env->scontext = 0;
}
--
2.43.0
On 2/26/25 11:39 AM, Florian Lugou wrote:
> scontext size is 16 bits on RV32 and 32 bits on RV64, as recommended by
> version 1.0 2025-02-21 of the debug specification.
>
> When the Smstateen extension is implemented, accessibility to the
> scontext CSR is controlled by bit 57 of the [mh]stateen0 CSRs.
>
> Signed-off-by: Florian Lugou <florian.lugou@provenrun.com>
> ---
Can you please rebase these patches on top of the maintainer's tree:
https://github.com/alistair23/qemu/tree/riscv-to-apply.next
This patch will have a conflict on cpu_bits.h in that tree.
Looks good otherwise. Thanks,
Daniel
> target/riscv/cpu.h | 1 +
> target/riscv/cpu_bits.h | 5 +++++
> target/riscv/csr.c | 36 ++++++++++++++++++++++++++++++++++++
> target/riscv/debug.c | 1 +
> 4 files changed, 43 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 97713681cb..e47200f409 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -430,6 +430,7 @@ struct CPUArchState {
> target_ulong tdata2[RV_MAX_TRIGGERS];
> target_ulong tdata3[RV_MAX_TRIGGERS];
> target_ulong mcontext;
> + target_ulong scontext;
> struct CPUBreakpoint *cpu_breakpoint[RV_MAX_TRIGGERS];
> struct CPUWatchpoint *cpu_watchpoint[RV_MAX_TRIGGERS];
> QEMUTimer *itrigger_timer[RV_MAX_TRIGGERS];
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index f97c48a394..add0bb9d0e 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -247,6 +247,9 @@
> #define CSR_SIEH 0x114
> #define CSR_SIPH 0x154
>
> +/* Supervisor-Level Sdtrig CSRs (debug) */
> +#define CSR_SCONTEXT 0x5a8
> +
> /* Hpervisor CSRs */
> #define CSR_HSTATUS 0x600
> #define CSR_HEDELEG 0x602
> @@ -959,4 +962,6 @@ typedef enum RISCVException {
> #define MCONTEXT64 0x0000000000001FFFULL
> #define MCONTEXT32_HCONTEXT 0x0000007F
> #define MCONTEXT64_HCONTEXT 0x0000000000003FFFULL
> +#define SCONTEXT32 0x0000FFFF
> +#define SCONTEXT64 0x00000000FFFFFFFFULL
> #endif
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index afb7544f07..1c1ac8ed67 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -3221,6 +3221,10 @@ static RISCVException write_mstateen0(CPURISCVState *env, int csrno,
> wr_mask |= SMSTATEEN0_P1P13;
> }
>
> + if (riscv_cpu_cfg(env)->debug) {
> + wr_mask |= SMSTATEEN0_HSCONTXT;
> + }
> +
> if (riscv_cpu_cfg(env)->ext_smaia || riscv_cpu_cfg(env)->ext_smcsrind) {
> wr_mask |= SMSTATEEN0_SVSLCT;
> }
> @@ -5053,6 +5057,35 @@ static RISCVException write_mcontext(CPURISCVState *env, int csrno,
> return RISCV_EXCP_NONE;
> }
>
> +static RISCVException read_scontext(CPURISCVState *env, int csrno,
> + target_ulong *val)
> +{
> + RISCVException ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSCONTXT);
> + if (ret != RISCV_EXCP_NONE) {
> + return ret;
> + }
> +
> + *val = env->scontext;
> + return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_scontext(CPURISCVState *env, int csrno,
> + target_ulong val)
> +{
> + bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;
> +
> + RISCVException ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSCONTXT);
> + if (ret != RISCV_EXCP_NONE) {
> + return ret;
> + }
> +
> + /* Spec suggest 16-bit for RV32 and 34-bit for RV64 */
> + target_ulong mask = rv32 ? SCONTEXT32 : SCONTEXT64;
> +
> + env->scontext = val & mask;
> + return RISCV_EXCP_NONE;
> +}
> +
> static RISCVException read_mnscratch(CPURISCVState *env, int csrno,
> target_ulong *val)
> {
> @@ -5705,6 +5738,9 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
> [CSR_SIEH] = { "sieh", aia_smode32, NULL, NULL, rmw_sieh },
> [CSR_SIPH] = { "siph", aia_smode32, NULL, NULL, rmw_siph },
>
> + /* Supervisor-Level Sdtrig CSRs (debug) */
> + [CSR_SCONTEXT] = { "scontext", debug, read_scontext, write_scontext },
> +
> [CSR_HSTATUS] = { "hstatus", hmode, read_hstatus, write_hstatus,
> .min_priv_ver = PRIV_VERSION_1_12_0 },
> [CSR_HEDELEG] = { "hedeleg", hmode, read_hedeleg, write_hedeleg,
> diff --git a/target/riscv/debug.c b/target/riscv/debug.c
> index f6241a80be..914a9ce0f8 100644
> --- a/target/riscv/debug.c
> +++ b/target/riscv/debug.c
> @@ -1086,4 +1086,5 @@ void riscv_trigger_reset_hold(CPURISCVState *env)
> }
>
> env->mcontext = 0;
> + env->scontext = 0;
> }
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