Re: [PATCH v2 10/10] tpm-buf: Add TPM buffer support header for standalone reuse

[Jarkko Sakkinen]

On Sat, Jul 11, 2026 at 09:01:10AM -0700, Ross Philipson wrote:
> Extract all the functions and definitions for TPM buffer handling
> and separate them into their own header.
> 
> Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxx>
> ---
>  drivers/char/tpm/tpm-buf.c |  3 +-
>  include/linux/tpm.h        | 34 +--------------------
>  include/linux/tpm_buf.h    | 60 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 63 insertions(+), 34 deletions(-)
>  create mode 100644 include/linux/tpm_buf.h
> 
> diff --git a/drivers/char/tpm/tpm-buf.c b/drivers/char/tpm/tpm-buf.c
> index 1e5c11c312a8..233e81d3f149 100644
> --- a/drivers/char/tpm/tpm-buf.c
> +++ b/drivers/char/tpm/tpm-buf.c
> @@ -4,7 +4,8 @@
>   */
>  
>  #include <linux/module.h>
> -#include <linux/tpm.h>
> +#include <linux/tpm_command.h>
> +#include <linux/tpm_buf.h>
>  
>  static void __tpm_buf_size_invariant(struct tpm_buf *buf, u16 buf_size)
>  {
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 598dd53a10d8..0db277af45c3 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -26,6 +26,7 @@
>  #include <crypto/aes.h>
>  
>  #include <linux/tpm_command.h>
> +#include <linux/tpm_buf.h>
>  
>  struct tpm_chip;
>  struct trusted_key_payload;
> @@ -200,44 +201,11 @@ enum tpm_chip_flags {
>  
>  #define to_tpm_chip(d) container_of(d, struct tpm_chip, dev)
>  
> -enum tpm_buf_flags {
> -	/* TPM2B format: */
> -	TPM_BUF_TPM2B		= BIT(0),
> -	/* The buffer is in invalid and unusable state: */
> -	TPM_BUF_INVALID		= BIT(1),
> -};
> -
> -/*
> - * A buffer for constructing and parsing TPM commands, responses and sized
> - * (TPM2B) buffers.
> - */
> -struct tpm_buf {
> -	u8 flags;
> -	u16 length;
> -	u16 capacity;
> -	u8 handles;
> -	u8 data[];
> -};
> -
>  struct tpm2_hash {
>  	unsigned int crypto_id;
>  	unsigned int tpm_id;
>  };
>  
> -void tpm_buf_init(struct tpm_buf *buf, u16 buf_size);
> -void tpm_buf_init_sized(struct tpm_buf *buf, u16 buf_size);
> -void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal);
> -void tpm_buf_reset_sized(struct tpm_buf *buf);
> -u16 tpm_buf_length(struct tpm_buf *buf);
> -void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length);
> -void tpm_buf_append_u8(struct tpm_buf *buf, const u8 value);
> -void tpm_buf_append_u16(struct tpm_buf *buf, const u16 value);
> -void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value);
> -u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset);
> -u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset);
> -u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset);
> -void tpm_buf_append_handle(struct tpm_buf *buf, u32 handle);
> -
>  /*
>   * Check if TPM device is in the firmware upgrade mode.
>   */
> diff --git a/include/linux/tpm_buf.h b/include/linux/tpm_buf.h
> new file mode 100644
> index 000000000000..f8c105d8b8bf
> --- /dev/null
> +++ b/include/linux/tpm_buf.h
> @@ -0,0 +1,60 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Following copyright information was take from the original file
> + * <include/linux/tpm.h> where the definitions were moved from:
> + *
> + * Copyright (C) 2004,2007,2008 IBM Corporation
> + *
> + * Authors:
> + * Leendert van Doorn <leendert@xxxxxxxxxxxxxx>
> + * Dave Safford <safford@xxxxxxxxxxxxxx>
> + * Reiner Sailer <sailer@xxxxxxxxxxxxxx>
> + * Kylene Hall <kjhall@xxxxxxxxxx>
> + * Debora Velarde <dvelarde@xxxxxxxxxx>
> + *
> + * Maintained by: <tpmdd_devel@xxxxxxxxxxxxxxxxxxxxx>
> + *
> + * Device driver for TCG/TCPA TPM (trusted platform module).
> + * Specifications at www.trustedcomputinggroup.org
> + */
> +
> +#ifndef __LINUX_TPM_BUF_H__
> +#define __LINUX_TPM_BUF_H__
> +
> +#include <linux/types.h>
> +#include <linux/bits.h>
> +
> +enum tpm_buf_flags {
> +	/* TPM2B format: */
> +	TPM_BUF_TPM2B		= BIT(0),
> +	/* The buffer is in invalid and unusable state: */
> +	TPM_BUF_INVALID		= BIT(1),
> +};
> +
> +/*
> + * A buffer for constructing and parsing TPM commands, responses and sized
> + * (TPM2B) buffers.
> + */
> +struct tpm_buf {
> +	u8 flags;
> +	u8 handles;
> +	u16 length;
> +	u16 capacity;
> +	u8 data[];
> +};
> +
> +void tpm_buf_init(struct tpm_buf *buf, u16 buf_size);
> +void tpm_buf_init_sized(struct tpm_buf *buf, u16 buf_size);
> +void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal);
> +void tpm_buf_reset_sized(struct tpm_buf *buf);
> +u16 tpm_buf_length(struct tpm_buf *buf);
> +void tpm_buf_append(struct tpm_buf *buf, const u8 *new_data, u16 new_length);
> +void tpm_buf_append_u8(struct tpm_buf *buf, const u8 value);
> +void tpm_buf_append_u16(struct tpm_buf *buf, const u16 value);
> +void tpm_buf_append_u32(struct tpm_buf *buf, const u32 value);
> +u8 tpm_buf_read_u8(struct tpm_buf *buf, off_t *offset);
> +u16 tpm_buf_read_u16(struct tpm_buf *buf, off_t *offset);
> +u32 tpm_buf_read_u32(struct tpm_buf *buf, off_t *offset);
> +void tpm_buf_append_handle(struct tpm_buf *buf, u32 handle);
> +
> +#endif
> -- 
> 2.55.0
> 

I would probably ack them all as I've seen these many times and
there's not much anything new. Just waiting for additional
feedback before applying them.

BR, Jarkko