[S] Change in coreboot[master]: acpi/acpi.c: Fix einj generation pointer arithmetics

[Felix Held (Code Review)]

Felix Held has submitted this change. ( https://review.coreboot.org/c/coreboot/+/69326 )

Change subject: acpi/acpi.c: Fix einj generation pointer arithmetics
......................................................................

acpi/acpi.c: Fix einj generation pointer arithmetics

Without a cast the aritmetics of

tat = einj + sizeof(acpi_einj_smi_t)

is the same as

tat = (uintptr_t)einj + size(acpi_einj_smi_t) * size(acpi_einj_smi_t)

So it overshoots the intended offset by a lot.

This issue only came apparent because now einj is in the small IMD
region which is close to TSEG. With the wrong aritmetics the tat
pointer ended up inside TSEG which is not accessible from the OS
causing exceptions.

TEST: observe that tat pointer is inside the small IMD below
TSEG (0x78000000 on our setup).
"acpi_create_einj trigger_action_table = 0x77ffe89c"

Change-Id: I3ab64b95c33eef01b2048816a21e17855bcb2f54
Signed-off-by: Arthur Heymans 
Signed-off-by: Jonathan Zhang 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69326
Tested-by: build bot (Jenkins) 
Reviewed-by: Marc Jones 
---
M src/acpi/acpi.c
1 file changed, 34 insertions(+), 1 deletion(-)

Approvals:
  build bot (Jenkins): Verified
  Marc Jones: Looks good to me, approved

diff --git a/src/acpi/acpi.c b/src/acpi/acpi.c
index 3ddb1d0..e1d4088 100644
--- a/src/acpi/acpi.c
+++ b/src/acpi/acpi.c
@@ -888,7 +888,7 @@

printk(BIOS_DEBUG, "%s einj_smi = %p\n", __func__, einj_smi);
    memset(einj_smi, 0, sizeof(acpi_einj_smi_t));
-	tat = (acpi_einj_trigger_table_t *)(einj_smi + sizeof(acpi_einj_smi_t));
+	tat = (acpi_einj_trigger_table_t *)((uint8_t *)einj_smi + sizeof(acpi_einj_smi_t));
    tat->header_size =  16;
    tat->revision =  0;
    tat->table_size =  sizeof(acpi_einj_trigger_table_t) +