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.mayd...@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 {

      STM32F2XXSPIState spi[STM_NUM_SPIS];
+
+    MemoryRegion sram;
+    MemoryRegion flash;
+    MemoryRegion flash_alias;
  };

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];

+
+    MemoryRegion sram;
+    MemoryRegion flash;
+    MemoryRegion flash_alias;
  };

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 *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);

-    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);

      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 *sram = g_new(MemoryRegion, 1);
-    MemoryRegion *flash = g_new(MemoryRegion, 1);
-    MemoryRegion *flash_alias = g_new(MemoryRegion, 1);

+    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, 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(&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);

      qdev_prop_set_uint32(armv7m, "num-irq", 96);

STM32F2XXUsartState usart[STM_NUM_USARTS]; #endif qemu_or_irq *adc_irqs; #endif MemoryRegion *system_memory = get_system_memory(); /* /* Init SRAM region */ /* Init ARMv7m */ MemoryRegion *system_memory = get_system_memory(); - memory_region_init_rom(flash, OBJECT(dev_soc), "STM32F205.flash", - memory_region_add_subregion(system_memory, FLASH_BASE_ADDRESS, flash); - memory_region_init_ram(sram, NULL, "STM32F205.sram", SRAM_SIZE, armv7m = DEVICE(&s->armv7m);

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

Thanks,
-- Alexandre

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