Re: [PATCH for-6.2 10/25] hw/arm: Don't allocate separate MemoryRegions in stm32 SoC realize

[Alexandre IOOSS]

On 8/12/21 11:33 AM, Peter Maydell wrote:
> In the realize methods of the stm32f100 and stm32f205 SoC objects, we
> call g_new() to create new MemoryRegion objjects for the sram, flash,
> and flash_alias.  This is unnecessary (and leaves open the
> possibility of leaking the allocations if we exit from realize with
> an error).  Make these MemoryRegions member fields of the device
> state struct instead, as stm32f405 already does.

There is a typo in "objjects".

This is something I had issue understanding as I was seeing both 
patterns in the codebase, thank you for making this clear.

> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   include/hw/arm/stm32f100_soc.h |  4 ++++
>   include/hw/arm/stm32f205_soc.h |  4 ++++
>   hw/arm/stm32f100_soc.c         | 17 +++++++----------
>   hw/arm/stm32f205_soc.c         | 17 +++++++----------
>   4 files changed, 22 insertions(+), 20 deletions(-)
>
> diff --git a/include/hw/arm/stm32f100_soc.h b/include/hw/arm/stm32f100_soc.h
> index 71bffcf4fd5..b7d71c6c634 100644
> --- a/include/hw/arm/stm32f100_soc.h
> +++ b/include/hw/arm/stm32f100_soc.h
> @@ -52,6 +52,10 @@ struct STM32F100State {
>   
>       STM32F2XXUsartState usart[STM_NUM_USARTS];
>       STM32F2XXSPIState spi[STM_NUM_SPIS];
> +
> +    MemoryRegion sram;
> +    MemoryRegion flash;
> +    MemoryRegion flash_alias;
>   };
>   
>   #endif
> diff --git a/include/hw/arm/stm32f205_soc.h b/include/hw/arm/stm32f205_soc.h
> index 985ff63aa9e..75251494917 100644
> --- a/include/hw/arm/stm32f205_soc.h
> +++ b/include/hw/arm/stm32f205_soc.h
> @@ -63,6 +63,10 @@ struct STM32F205State {
>       STM32F2XXSPIState spi[STM_NUM_SPIS];
>   
>       qemu_or_irq *adc_irqs;
> +
> +    MemoryRegion sram;
> +    MemoryRegion flash;
> +    MemoryRegion flash_alias;
>   };
>   
>   #endif
> diff --git a/hw/arm/stm32f100_soc.c b/hw/arm/stm32f100_soc.c
> index 0c4a5c66451..0be92b2c475 100644
> --- a/hw/arm/stm32f100_soc.c
> +++ b/hw/arm/stm32f100_soc.c
> @@ -67,25 +67,22 @@ static void stm32f100_soc_realize(DeviceState *dev_soc, 
> Error **errp)
>       int i;
>   
>       MemoryRegion *system_memory = get_system_memory();
> -    MemoryRegion *sram = g_new(MemoryRegion, 1);
> -    MemoryRegion *flash = g_new(MemoryRegion, 1);
> -    MemoryRegion *flash_alias = g_new(MemoryRegion, 1);
>   
>       /*
>        * Init flash region
>        * Flash starts at 0x08000000 and then is aliased to boot memory at 0x0
>        */
> -    memory_region_init_rom(flash, OBJECT(dev_soc), "STM32F100.flash",
> +    memory_region_init_rom(&s->flash, OBJECT(dev_soc), "STM32F100.flash",
>                              FLASH_SIZE, &error_fatal);
> -    memory_region_init_alias(flash_alias, OBJECT(dev_soc),
> -                             "STM32F100.flash.alias", flash, 0, FLASH_SIZE);
> -    memory_region_add_subregion(system_memory, FLASH_BASE_ADDRESS, flash);
> -    memory_region_add_subregion(system_memory, 0, flash_alias);
> +    memory_region_init_alias(&s->flash_alias, OBJECT(dev_soc),
> +                             "STM32F100.flash.alias", &s->flash, 0, 
> FLASH_SIZE);
> +    memory_region_add_subregion(system_memory, FLASH_BASE_ADDRESS, &s->flash);
> +    memory_region_add_subregion(system_memory, 0, &s->flash_alias);
>   
>       /* Init SRAM region */
> -    memory_region_init_ram(sram, NULL, "STM32F100.sram", SRAM_SIZE,
> +    memory_region_init_ram(&s->sram, NULL, "STM32F100.sram", SRAM_SIZE,
>                              &error_fatal);
> -    memory_region_add_subregion(system_memory, SRAM_BASE_ADDRESS, sram);
> +    memory_region_add_subregion(system_memory, SRAM_BASE_ADDRESS, &s->sram);
>   
>       /* Init ARMv7m */
>       armv7m = DEVICE(&s->armv7m);
> diff --git a/hw/arm/stm32f205_soc.c b/hw/arm/stm32f205_soc.c
> index 9cd41bf56da..0bd215aebd7 100644
> --- a/hw/arm/stm32f205_soc.c
> +++ b/hw/arm/stm32f205_soc.c
> @@ -84,21 +84,18 @@ static void stm32f205_soc_realize(DeviceState *dev_soc, 
> Error **errp)
>       int i;
>   
>       MemoryRegion *system_memory = get_system_memory();
> -    MemoryRegion *sram = g_new(MemoryRegion, 1);
> -    MemoryRegion *flash = g_new(MemoryRegion, 1);
> -    MemoryRegion *flash_alias = g_new(MemoryRegion, 1);
>   
> -    memory_region_init_rom(flash, OBJECT(dev_soc), "STM32F205.flash",
> +    memory_region_init_rom(&s->flash, OBJECT(dev_soc), "STM32F205.flash",
>                              FLASH_SIZE, &error_fatal);
> -    memory_region_init_alias(flash_alias, OBJECT(dev_soc),
> -                             "STM32F205.flash.alias", flash, 0, FLASH_SIZE);
> +    memory_region_init_alias(&s->flash_alias, OBJECT(dev_soc),
> +                             "STM32F205.flash.alias", &s->flash, 0, 
> FLASH_SIZE);
>   
> -    memory_region_add_subregion(system_memory, FLASH_BASE_ADDRESS, flash);
> -    memory_region_add_subregion(system_memory, 0, flash_alias);
> +    memory_region_add_subregion(system_memory, FLASH_BASE_ADDRESS, &s->flash);
> +    memory_region_add_subregion(system_memory, 0, &s->flash_alias);
>   
> -    memory_region_init_ram(sram, NULL, "STM32F205.sram", SRAM_SIZE,
> +    memory_region_init_ram(&s->sram, NULL, "STM32F205.sram", SRAM_SIZE,
>                              &error_fatal);
> -    memory_region_add_subregion(system_memory, SRAM_BASE_ADDRESS, sram);
> +    memory_region_add_subregion(system_memory, SRAM_BASE_ADDRESS, &s->sram);
>   
>       armv7m = DEVICE(&s->armv7m);
>       qdev_prop_set_uint32(armv7m, "num-irq", 96);

Reviewed-by: Alexandre Iooss <erdnaxe@crans.org>

Thanks,
-- Alexandre

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