Re: [PATCH] target/arm: gdbstub: Guard M-profile code with CONFIG_TCG

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 28/6/23 18:48, Fabiano Rosas wrote:
> This code is only relevant when TCG is present in the build. Building
> with --disable-tcg --enable-xen on an x86 host we get:
> 
> $ ../configure --target-list=x86_64-softmmu,aarch64-softmmu --disable-tcg --enable-xen
> $ make -j$(nproc)
> ...
> libqemu-aarch64-softmmu.fa.p/target_arm_gdbstub.c.o: in function `m_sysreg_ptr':
>   ../target/arm/gdbstub.c:358: undefined reference to `arm_v7m_get_sp_ptr'
>   ../target/arm/gdbstub.c:361: undefined reference to `arm_v7m_get_sp_ptr'
> 
> libqemu-aarch64-softmmu.fa.p/target_arm_gdbstub.c.o: in function `arm_gdb_get_m_systemreg':
> ../target/arm/gdbstub.c:405: undefined reference to `arm_v7m_mrs_control'
> 
> Signed-off-by: Fabiano Rosas <farosas@suse.de>
> ---
> This is a respin of:
> https://lore.kernel.org/r/20230313151058.19645-5-farosas@suse.de
> ---
>   target/arm/gdbstub.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/target/arm/gdbstub.c b/target/arm/gdbstub.c
> index 03b17c814f..f421c5d041 100644
> --- a/target/arm/gdbstub.c
> +++ b/target/arm/gdbstub.c
> @@ -324,6 +324,7 @@ static int arm_gen_dynamic_sysreg_xml(CPUState *cs, int base_reg)
>       return cpu->dyn_sysreg_xml.num;
>   }
>   
> +#ifdef CONFIG_TCG

OK.

>   typedef enum {
>       M_SYSREG_MSP,
>       M_SYSREG_PSP,
> @@ -481,6 +482,7 @@ static int arm_gen_dynamic_m_secextreg_xml(CPUState *cs, int orig_base_reg)
>       return cpu->dyn_m_secextreg_xml.num;
>   }
>   #endif
> +#endif /* CONFIG_TCG */
>   
>   const char *arm_gdb_get_dynamic_xml(CPUState *cs, const char *xmlname)
>   {
> @@ -561,6 +563,7 @@ void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu)
>                                arm_gen_dynamic_sysreg_xml(cs, cs->gdb_num_regs),
>                                "system-registers.xml", 0);
>   
> +#ifdef CONFIG_TCG

IIUC tcg_enabled(), this guard shouldn't be necessary; if CONFIG_TCG
is not defined, tcg_enabled() evaluates to 0, and the compiler should
elide the whole block.

>       if (arm_feature(env, ARM_FEATURE_M) && tcg_enabled()) {
>           gdb_register_coprocessor(cs,
>               arm_gdb_get_m_systemreg, arm_gdb_set_m_systemreg,
> @@ -575,4 +578,5 @@ void arm_cpu_register_gdb_regs_for_features(ARMCPU *cpu)
>           }
>   #endif
>       }
> +#endif /* CONFIG_TCG */
>   }