linux/drivers/char/tpm/tpm_tis_core.h
Kees Cook 3c8ba0d61d kernel.h: Retain constant expression output for max()/min()
In the effort to remove all VLAs from the kernel[1], it is desirable to
build with -Wvla.  However, this warning is overly pessimistic, in that
it is only happy with stack array sizes that are declared as constant
expressions, and not constant values.  One case of this is the
evaluation of the max() macro which, due to its construction, ends up
converting constant expression arguments into a constant value result.

All attempts to rewrite this macro with __builtin_constant_p() failed
with older compilers (e.g.  gcc 4.4)[2].  However, Martin Uecker,
constructed[3] a mind-shattering solution that works everywhere.
Cthulhu fhtagn!

This patch updates the min()/max() macros to evaluate to a constant
expression when called on constant expression arguments.  This removes
several false-positive stack VLA warnings from an x86 allmodconfig build
when -Wvla is added:

  $ diff -u before.txt after.txt | grep ^-
  -drivers/input/touchscreen/cyttsp4_core.c:871:2: warning: ISO C90 forbids variable length array ‘ids’ [-Wvla]
  -fs/btrfs/tree-checker.c:344:4: warning: ISO C90 forbids variable length array ‘namebuf’ [-Wvla]
  -lib/vsprintf.c:747:2: warning: ISO C90 forbids variable length array ‘sym’ [-Wvla]
  -net/ipv4/proc.c:403:2: warning: ISO C90 forbids variable length array ‘buff’ [-Wvla]
  -net/ipv6/proc.c:198:2: warning: ISO C90 forbids variable length array ‘buff’ [-Wvla]
  -net/ipv6/proc.c:218:2: warning: ISO C90 forbids variable length array ‘buff64’ [-Wvla]

This also updates two cases where different enums were being compared
and explicitly casts them to int (which matches the old side-effect of
the single-evaluation code): one in tpm/tpm_tis_core.h, and one in
drm/drm_color_mgmt.c.

 [1] https://lkml.org/lkml/2018/3/7/621
 [2] https://lkml.org/lkml/2018/3/10/170
 [3] https://lkml.org/lkml/2018/3/20/845

Co-Developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Co-Developed-by: Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-05 14:17:16 -07:00

173 lines
4.7 KiB
C

/*
* Copyright (C) 2005, 2006 IBM Corporation
* Copyright (C) 2014, 2015 Intel Corporation
*
* Authors:
* Leendert van Doorn <leendert@watson.ibm.com>
* Kylene Hall <kjhall@us.ibm.com>
*
* Maintained by: <tpmdd-devel@lists.sourceforge.net>
*
* Device driver for TCG/TCPA TPM (trusted platform module).
* Specifications at www.trustedcomputinggroup.org
*
* This device driver implements the TPM interface as defined in
* the TCG TPM Interface Spec version 1.2, revision 1.0.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*/
#ifndef __TPM_TIS_CORE_H__
#define __TPM_TIS_CORE_H__
#include "tpm.h"
enum tis_access {
TPM_ACCESS_VALID = 0x80,
TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
TPM_ACCESS_REQUEST_PENDING = 0x04,
TPM_ACCESS_REQUEST_USE = 0x02,
};
enum tis_status {
TPM_STS_VALID = 0x80,
TPM_STS_COMMAND_READY = 0x40,
TPM_STS_GO = 0x20,
TPM_STS_DATA_AVAIL = 0x10,
TPM_STS_DATA_EXPECT = 0x08,
};
enum tis_int_flags {
TPM_GLOBAL_INT_ENABLE = 0x80000000,
TPM_INTF_BURST_COUNT_STATIC = 0x100,
TPM_INTF_CMD_READY_INT = 0x080,
TPM_INTF_INT_EDGE_FALLING = 0x040,
TPM_INTF_INT_EDGE_RISING = 0x020,
TPM_INTF_INT_LEVEL_LOW = 0x010,
TPM_INTF_INT_LEVEL_HIGH = 0x008,
TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
TPM_INTF_STS_VALID_INT = 0x002,
TPM_INTF_DATA_AVAIL_INT = 0x001,
};
enum tis_defaults {
TIS_MEM_LEN = 0x5000,
TIS_SHORT_TIMEOUT = 750, /* ms */
TIS_LONG_TIMEOUT = 2000, /* 2 sec */
};
/* Some timeout values are needed before it is known whether the chip is
* TPM 1.0 or TPM 2.0.
*/
#define TIS_TIMEOUT_A_MAX max_t(int, TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_A)
#define TIS_TIMEOUT_B_MAX max_t(int, TIS_LONG_TIMEOUT, TPM2_TIMEOUT_B)
#define TIS_TIMEOUT_C_MAX max_t(int, TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_C)
#define TIS_TIMEOUT_D_MAX max_t(int, TIS_SHORT_TIMEOUT, TPM2_TIMEOUT_D)
#define TPM_ACCESS(l) (0x0000 | ((l) << 12))
#define TPM_INT_ENABLE(l) (0x0008 | ((l) << 12))
#define TPM_INT_VECTOR(l) (0x000C | ((l) << 12))
#define TPM_INT_STATUS(l) (0x0010 | ((l) << 12))
#define TPM_INTF_CAPS(l) (0x0014 | ((l) << 12))
#define TPM_STS(l) (0x0018 | ((l) << 12))
#define TPM_STS3(l) (0x001b | ((l) << 12))
#define TPM_DATA_FIFO(l) (0x0024 | ((l) << 12))
#define TPM_DID_VID(l) (0x0F00 | ((l) << 12))
#define TPM_RID(l) (0x0F04 | ((l) << 12))
#define LPC_CNTRL_OFFSET 0x84
#define LPC_CLKRUN_EN (1 << 2)
#define INTEL_LEGACY_BLK_BASE_ADDR 0xFED08000
#define ILB_REMAP_SIZE 0x100
enum tpm_tis_flags {
TPM_TIS_ITPM_WORKAROUND = BIT(0),
};
struct tpm_tis_data {
u16 manufacturer_id;
int locality;
int irq;
bool irq_tested;
unsigned int flags;
void __iomem *ilb_base_addr;
u16 clkrun_enabled;
wait_queue_head_t int_queue;
wait_queue_head_t read_queue;
const struct tpm_tis_phy_ops *phy_ops;
};
struct tpm_tis_phy_ops {
int (*read_bytes)(struct tpm_tis_data *data, u32 addr, u16 len,
u8 *result);
int (*write_bytes)(struct tpm_tis_data *data, u32 addr, u16 len,
const u8 *value);
int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result);
int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result);
int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src);
};
static inline int tpm_tis_read_bytes(struct tpm_tis_data *data, u32 addr,
u16 len, u8 *result)
{
return data->phy_ops->read_bytes(data, addr, len, result);
}
static inline int tpm_tis_read8(struct tpm_tis_data *data, u32 addr, u8 *result)
{
return data->phy_ops->read_bytes(data, addr, 1, result);
}
static inline int tpm_tis_read16(struct tpm_tis_data *data, u32 addr,
u16 *result)
{
return data->phy_ops->read16(data, addr, result);
}
static inline int tpm_tis_read32(struct tpm_tis_data *data, u32 addr,
u32 *result)
{
return data->phy_ops->read32(data, addr, result);
}
static inline int tpm_tis_write_bytes(struct tpm_tis_data *data, u32 addr,
u16 len, const u8 *value)
{
return data->phy_ops->write_bytes(data, addr, len, value);
}
static inline int tpm_tis_write8(struct tpm_tis_data *data, u32 addr, u8 value)
{
return data->phy_ops->write_bytes(data, addr, 1, &value);
}
static inline int tpm_tis_write32(struct tpm_tis_data *data, u32 addr,
u32 value)
{
return data->phy_ops->write32(data, addr, value);
}
static inline bool is_bsw(void)
{
#ifdef CONFIG_X86
return ((boot_cpu_data.x86_model == INTEL_FAM6_ATOM_AIRMONT) ? 1 : 0);
#else
return false;
#endif
}
void tpm_tis_remove(struct tpm_chip *chip);
int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
const struct tpm_tis_phy_ops *phy_ops,
acpi_handle acpi_dev_handle);
#ifdef CONFIG_PM_SLEEP
int tpm_tis_resume(struct device *dev);
#endif
#endif