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From: Richard Henderson <richard.henderson@linaro.org>
To: Jiajie Chen <c@jia.je>, qemu-devel@nongnu.org
Cc: yijun@loongson.cn, shenjinyang@loongson.cn, gaosong@loongson.cn,
	i.qemu@xen0n.name
Subject: Re: [PATCH v4 03/11] target/loongarch: Add GDB support for loongarch32 mode
Date: Tue, 8 Aug 2023 11:34:12 -0700	[thread overview]
Message-ID: <44e5fb7c-4773-b8a1-5eac-c656c4a0a92f@linaro.org> (raw)
In-Reply-To: <20230808015506.1705140-4-c@jia.je>

On 8/7/23 18:54, Jiajie Chen wrote:
> GPRs and PC are 32-bit wide in loongarch32 mode.
> 
> Signed-off-by: Jiajie Chen <c@jia.je>
> ---
>   configs/targets/loongarch64-softmmu.mak |  2 +-
>   gdb-xml/loongarch-base32.xml            | 45 +++++++++++++++++++++++++
>   target/loongarch/cpu.c                  | 10 +++++-
>   target/loongarch/gdbstub.c              | 32 ++++++++++++++----
>   4 files changed, 80 insertions(+), 9 deletions(-)
>   create mode 100644 gdb-xml/loongarch-base32.xml
> 
> diff --git a/configs/targets/loongarch64-softmmu.mak b/configs/targets/loongarch64-softmmu.mak
> index 9abc99056f..f23780fdd8 100644
> --- a/configs/targets/loongarch64-softmmu.mak
> +++ b/configs/targets/loongarch64-softmmu.mak
> @@ -1,5 +1,5 @@
>   TARGET_ARCH=loongarch64
>   TARGET_BASE_ARCH=loongarch
>   TARGET_SUPPORTS_MTTCG=y
> -TARGET_XML_FILES= gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml
> +TARGET_XML_FILES= gdb-xml/loongarch-base32.xml gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml
>   TARGET_NEED_FDT=y
> diff --git a/gdb-xml/loongarch-base32.xml b/gdb-xml/loongarch-base32.xml
> new file mode 100644
> index 0000000000..af47bbd3da
> --- /dev/null
> +++ b/gdb-xml/loongarch-base32.xml
> @@ -0,0 +1,45 @@
> +<?xml version="1.0"?>
> +<!-- Copyright (C) 2022 Free Software Foundation, Inc.
> +
> +     Copying and distribution of this file, with or without modification,
> +     are permitted in any medium without royalty provided the copyright
> +     notice and this notice are preserved.  -->
> +
> +<!DOCTYPE feature SYSTEM "gdb-target.dtd">
> +<feature name="org.gnu.gdb.loongarch.base">
> +  <reg name="r0" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r1" bitsize="32" type="code_ptr" group="general"/>
> +  <reg name="r2" bitsize="32" type="data_ptr" group="general"/>
> +  <reg name="r3" bitsize="32" type="data_ptr" group="general"/>
> +  <reg name="r4" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r5" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r6" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r7" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r8" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r9" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r10" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r11" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r12" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r13" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r14" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r15" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r16" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r17" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r18" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r19" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r20" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r21" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r22" bitsize="32" type="data_ptr" group="general"/>
> +  <reg name="r23" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r24" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r25" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r26" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r27" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r28" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r29" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r30" bitsize="32" type="uint32" group="general"/>
> +  <reg name="r31" bitsize="32" type="uint32" group="general"/>
> +  <reg name="orig_a0" bitsize="32" type="uint32" group="general"/>
> +  <reg name="pc" bitsize="32" type="code_ptr" group="general"/>
> +  <reg name="badv" bitsize="32" type="code_ptr" group="general"/>
> +</feature>
> diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
> index 3bd293d00a..13d4fccbd3 100644
> --- a/target/loongarch/cpu.c
> +++ b/target/loongarch/cpu.c
> @@ -694,7 +694,13 @@ static const struct SysemuCPUOps loongarch_sysemu_ops = {
>   
>   static gchar *loongarch_gdb_arch_name(CPUState *cs)
>   {
> -    return g_strdup("loongarch64");
> +    LoongArchCPU *cpu = LOONGARCH_CPU(cs);
> +    CPULoongArchState *env = &cpu->env;
> +    if (LOONGARCH_CPUCFG_ARCH(env, LA64)) {
> +        return g_strdup("loongarch64");
> +    } else {
> +        return g_strdup("loongarch32");
> +    }
>   }
>   
>   static void loongarch_cpu_class_init(ObjectClass *c, void *data)
> @@ -734,6 +740,8 @@ static void loongarch_cpu_class_init(ObjectClass *c, void *data)
>   
>   static void loongarch32_cpu_class_init(ObjectClass *c, void *data)
>   {
> +    CPUClass *cc = CPU_CLASS(c);
> +    cc->gdb_core_xml_file = "loongarch-base32.xml";
>   }
>   
>   #define DEFINE_LOONGARCH_CPU_TYPE(model, initfn) \
> diff --git a/target/loongarch/gdbstub.c b/target/loongarch/gdbstub.c
> index 0752fff924..0dfd1c8bb9 100644
> --- a/target/loongarch/gdbstub.c
> +++ b/target/loongarch/gdbstub.c
> @@ -34,16 +34,25 @@ int loongarch_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
>   {
>       LoongArchCPU *cpu = LOONGARCH_CPU(cs);
>       CPULoongArchState *env = &cpu->env;
> +    uint64_t val;
>   
>       if (0 <= n && n < 32) {
> -        return gdb_get_regl(mem_buf, env->gpr[n]);
> +        val = env->gpr[n];
>       } else if (n == 32) {
>           /* orig_a0 */
> -        return gdb_get_regl(mem_buf, 0);
> +        val = 0;
>       } else if (n == 33) {
> -        return gdb_get_regl(mem_buf, env->pc);
> +        val = env->pc;
>       } else if (n == 34) {
> -        return gdb_get_regl(mem_buf, env->CSR_BADV);
> +        val = env->CSR_BADV;
> +    }
> +
> +    if (0 <= n && n <= 34) {
> +        if (LOONGARCH_CPUCFG_ARCH(env, LA64)) {
> +            return gdb_get_reg64(mem_buf, val);
> +        } else {
> +            return gdb_get_reg32(mem_buf, val);
> +        }

Is it an existing bug that BADV is readable...


> @@ -52,15 +61,24 @@ int loongarch_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
>   {
>       LoongArchCPU *cpu = LOONGARCH_CPU(cs);
>       CPULoongArchState *env = &cpu->env;
> -    target_ulong tmp = ldtul_p(mem_buf);
> +    target_ulong tmp;
> +    int read_length;
>       int length = 0;
>   
> +    if (LOONGARCH_CPUCFG_ARCH(env, LA64)) {
> +        tmp = ldq_p(mem_buf);
> +        read_length = 8;
> +    } else {
> +        tmp = ldl_p(mem_buf);
> +        read_length = 4;
> +    }
> +
>       if (0 <= n && n < 32) {
>           env->gpr[n] = tmp;
> -        length = sizeof(target_ulong);
> +        length = read_length;
>       } else if (n == 33) {
>           env->pc = tmp;
> -        length = sizeof(target_ulong);
> +        length = read_length;
>       }

... but not writable?  I can't immediately see any reason why gdbstub should reject writes 
to BADV.

But for this patch:
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~



  reply	other threads:[~2023-08-08 18:35 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-08  1:54 [PATCH v4 00/11] Add la32 & va32 mode for loongarch64-softmmu Jiajie Chen
2023-08-08  1:54 ` [PATCH v4 01/11] target/loongarch: Add macro to check current arch Jiajie Chen
2023-08-08 17:01   ` Richard Henderson
2023-08-08 17:13     ` Jiajie Chen
2023-08-10 11:08       ` Philippe Mathieu-Daudé
2023-08-10 11:06   ` Philippe Mathieu-Daudé
2023-08-08  1:54 ` [PATCH v4 02/11] target/loongarch: Add new object class for loongarch32 cpus Jiajie Chen
2023-08-08 18:19   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 03/11] target/loongarch: Add GDB support for loongarch32 mode Jiajie Chen
2023-08-08 18:34   ` Richard Henderson [this message]
2023-08-08  1:54 ` [PATCH v4 04/11] target/loongarch: Support LoongArch32 TLB entry Jiajie Chen
2023-08-08 18:37   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 05/11] target/loongarch: Support LoongArch32 DMW Jiajie Chen
2023-08-08 18:37   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 06/11] target/loongarch: Support LoongArch32 VPPN Jiajie Chen
2023-08-08 18:38   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 07/11] target/loongarch: Add LA32 & VA32 to DisasContext Jiajie Chen
2023-08-08 18:40   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 08/11] target/loongarch: Reject la64-only instructions in la32 mode Jiajie Chen
2023-08-08 18:48   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 09/11] target/loongarch: Truncate high 32 bits of address in VA32 mode Jiajie Chen
2023-08-08 19:08   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 10/11] target/loongarch: Sign extend results " Jiajie Chen
2023-08-08 19:12   ` Richard Henderson
2023-08-08  1:54 ` [PATCH v4 11/11] target/loongarch: Add loongarch32 cpu la132 Jiajie Chen
2023-08-08  1:59   ` Jiajie Chen
2023-08-08 19:26   ` Richard Henderson
2023-08-09  7:31     ` Jiajie Chen

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