edk2/MdePkg/Library/BaseLib/SwitchStack.c
Mingjie Shen f57a4f1216 MdePkg: Replace manual alignment checks with helper macros
Replace manual alignment checks with IS_ALIGNED() and
ADDRESS_IS_ALIGNED().

Convert the following bitmask and modulo forms:

- ((E & ((PowOf2Expr) - ONE)) == ZERO)
- ((E & ((PowOf2Expr) - ONE)) != ZERO)
- ((E % (PowOf2Expr)) == ZERO)
- ((E % (PowOf2Expr)) != ZERO)

to the corresponding helper macro forms:

+ IS_ALIGNED (E, PowOf2Expr)
+ !IS_ALIGNED (E, PowOf2Expr)

PowOf2Expr is limited to known power-of-two expressions, including
SIZE_* and BASE_* macros, EFI_PAGE_SIZE, CPU_STACK_ALIGNMENT,
RUNTIME_PAGE_ALLOCATION_GRANULARITY, sizeof() of UEFI integer types
(e.g. BOOLEAN, CHAR16, UINT32, UINTN) and pointer types, and 1 << E1
expressions.

Address checks that cast the checked value to UINTN are written with
ADDRESS_IS_ALIGNED().

The change was generated with the Coccinelle semantic patch below.

```smpl
@power_of_2_expr@
expression PowOf2Expr;
expression E1;
typedef BOOLEAN, CHAR8, CHAR16, INT8, UINT8, INT16, UINT16, INT32, UINT32, INT64, UINT64, INTN, UINTN;
type ScalarType = { BOOLEAN, CHAR8, CHAR16, INT8, UINT8, INT16, UINT16, INT32, UINT32, INT64, UINT64, INTN, UINTN };
type AnyType;
type PointerType = AnyType *;
idexpression ScalarType ScalarValue;
idexpression PointerType PointerValue;
constant SizeBase =~ "^(SIZE|BASE)_(1|2|4|8|16|32|64|128|256|512)[KMGTPE]B$";
constant NamedPowerOf2 =~ "^(EFI_PAGE_SIZE|CPU_STACK_ALIGNMENT|RUNTIME_PAGE_ALLOCATION_GRANULARITY)$";
constant ONE = {1, 1U, 1u};
@@
(
(
  SizeBase
|
  NamedPowerOf2
|
  ONE << E1
|
  sizeof (ScalarType)
|
  sizeof (PointerType)
|
  sizeof (ScalarValue)
|
  sizeof (PointerValue)
)
&
PowOf2Expr
)

@aligned depends on power_of_2_expr disable is_zero,isnt_zero@
expression E;
expression power_of_2_expr.PowOf2Expr;
constant ONE = {1, 1U, 1u};
constant ZERO = {0, 0U, 0u};
@@
(
  ((E & (E - ONE)) == ZERO)
|
- ((E & ((PowOf2Expr) - ONE)) == ZERO)
+ IS_ALIGNED (E, PowOf2Expr)
|
  ((E & (E - ONE)) != ZERO)
|
- ((E & ((PowOf2Expr) - ONE)) != ZERO)
+ !IS_ALIGNED (E, PowOf2Expr)
|
- ((E % (PowOf2Expr)) == ZERO)
+ IS_ALIGNED (E, PowOf2Expr)
|
- ((E % (PowOf2Expr)) != ZERO)
+ !IS_ALIGNED (E, PowOf2Expr)
)

@address_is_aligned@
typedef UINTN;
expression *Address;
expression Alignment;
@@
- IS_ALIGNED ((UINTN) Address, Alignment)
+ ADDRESS_IS_ALIGNED (Address, Alignment)

@normalize_aligned disable paren expression@
expression E, SZ;
@@
(
- (IS_ALIGNED (E, SZ))
+ IS_ALIGNED (E, SZ)
|
- (!IS_ALIGNED (E, SZ))
+ !IS_ALIGNED (E, SZ)
)

@normalize_macro_args disable paren expression@
expression E, SZ;
@@
(
- IS_ALIGNED ((E), SZ)
+ IS_ALIGNED (E, SZ)
|
- IS_ALIGNED (E, (SZ))
+ IS_ALIGNED (E, SZ)
)
```

Signed-off-by: Mingjie Shen <shen497@purdue.edu>
2026-06-09 07:20:10 +00:00

70 lines
2.2 KiB
C

/** @file
Switch Stack functions.
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "BaseLibInternals.h"
/**
Transfers control to a function starting with a new stack.
Transfers control to the function specified by EntryPoint using the
new stack specified by NewStack and passing in the parameters specified
by Context1 and Context2. Context1 and Context2 are optional and may
be NULL. The function EntryPoint must never return. This function
supports a variable number of arguments following the NewStack parameter.
These additional arguments are ignored on IA-32, x64, and EBC.
IPF CPUs expect one additional parameter of type VOID * that specifies
the new backing store pointer.
If EntryPoint is NULL, then ASSERT().
If NewStack is NULL, then ASSERT().
@param EntryPoint A pointer to function to call with the new stack.
@param Context1 A pointer to the context to pass into the EntryPoint
function.
@param Context2 A pointer to the context to pass into the EntryPoint
function.
@param NewStack A pointer to the new stack to use for the EntryPoint
function.
@param ... This variable argument list is ignored for IA32, x64, and EBC.
For IPF, this variable argument list is expected to contain
a single parameter of type VOID * that specifies the new backing
store pointer.
**/
VOID
EFIAPI
SwitchStack (
IN SWITCH_STACK_ENTRY_POINT EntryPoint,
IN VOID *Context1 OPTIONAL,
IN VOID *Context2 OPTIONAL,
IN VOID *NewStack,
...
)
{
VA_LIST Marker;
ASSERT (EntryPoint != NULL);
ASSERT (NewStack != NULL);
//
// New stack must be aligned with CPU_STACK_ALIGNMENT
//
ASSERT (ADDRESS_IS_ALIGNED (NewStack, CPU_STACK_ALIGNMENT));
VA_START (Marker, NewStack);
InternalSwitchStack (EntryPoint, Context1, Context2, NewStack, Marker);
VA_END (Marker);
//
// InternalSwitchStack () will never return
//
ASSERT (FALSE);
}